Our insurance products primarily include commercial property and casualty coverages, including surety. Our services include warranty, risk management information services and claims administration. Our products and services are primarily marketed through independent agents, brokers and managing general underwriters to a wide variety of customers, including small, medium and large businesses, insurance companies, associations, professionals and other groups.

Our commercial property & casualty underwriting operations presence in the United States of America (U.S.) consists of field underwriting locations and centralized processing operations which handle policy processing, billing and collection activities and also act as call centers to optimize service. Our claim operations in the U.S. consists of primary locations where we handle multiple claim types and key business functions, as well as regional claim offices which are aligned with our underwriting field structure. We have property & casualty underwriting operations in Canada, the United Kingdom (U.K.) and Continental Europe, as well as access to business placed at Lloyd's of London through Syndicate 382.

Our commercial property and casualty insurance operations are managed and reported in three business segments: Specialty, Commercial and International, which we refer to collectively as Property & Casualty Operations. Our operations outside of Property & Casualty Operations are managed and reported in two business segments: Life & Group and Corporate & Other. Each segment is managed separately due to differences in their markets and product mix. Discussion of each segment, including the products offered, customers served and distribution channels used, is set forth in the Management's Discussion and Analysis (MD&A) included under Item 7 and in Note O to the Consolidated Financial Statements included under Item 8.

The property and casualty insurance industry is highly competitive both as to rate and service. We compete with a large number of stock and mutual insurance companies and other entities for both distributors and customers. Insurers compete on the basis of factors including products, price, services, ratings and financial strength. Accordingly, we must continuously allocate resources to refine and improve our insurance products and services.

The insurance industry is subject to comprehensive and detailed regulation and supervision. Regulatory oversight by applicable agencies is exercised through review of submitted filings and information, examinations (both financial and market conduct), direct inquiries and interviews. Each domestic and foreign jurisdiction has established supervisory agencies with broad administrative powers relative to licensing insurers and agents, approving policy forms, establishing reserve requirements, prescribing the form and content of statutory financial reports and regulating capital adequacy and the type, quality and amount of investments permitted. Such regulatory powers also extend to corporate governance requirements, risk assessmentmanagement practices and disclosures and premium rate regulations requiring rates not be excessive, inadequate or unfairly discriminatory. In addition to regulation of dividends by insurance subsidiaries, intercompany transfers of assets or payments may be subject to prior notice or approval by insurance regulators, depending on the size of such transfers and payments in relation to the financial position of the insurance subsidiaries making the transfer or payment.payments.

Domestic insurers are also required by state insurance regulators to provide coverage to certain insureds who would not otherwise be considered eligible by the insurers. Each state dictates the types of insurance and the level of coverage that must be provided to such involuntary risks. Our share of these involuntary risks is mandatory and generally a function of our respective share of the voluntary market by line of insurance in each state.

Further, domestic insurance companies are subject to state guaranty fund and other insurance-related assessments. Guaranty funds are governed by state insurance guaranty associations which levy assessments to meet the funding needs of insolvent insurer estates. Other insurance-related assessments are generally levied by state agencies to fund various organizations, including disaster relief funds, rating bureaus, insurance departments and workers'

As ourAlthough the U.S. federal government does not currently directly regulate the business of insurance, operations are conducted infederal legislative and regulatory initiatives can affect the insurance industry. These initiatives and legislation include proposals relating to terrorism and natural catastrophe exposures, cybersecurity risk management, federal financial services reforms and certain tax reforms.

The Terrorism Risk Insurance Program Reauthorization Act of 2019 (TRIPRA) provides for a multitudefederal government backstop for insured terrorism risks through 2027. The mitigating effect of both domestic and foreign jurisdictions, we are subject to a numbersuch law is part of regulatory agency requirements applicable to a portion, or all,the analysis of our operations. These include butoverall risk posture for terrorism and, accordingly, our risk positioning may change if such law was modified.

We also continue to invest in the security of our systems and network on an enterprise-wide basis. This requires investment of a significant amount of resources by us on an ongoing basis. Potential implications of possible cybersecurity legislation on such current investment, if any, are not limiteduncertain.

The foregoing laws, regulations and proposals, either separately or in the aggregate, create a regulatory and legal environment that may require changes in our business plan or significant investment of resources in order to operate in an effective and compliant manner.

Additionally, various legislative and regulatory efforts to reform the Statetort liability system have, and will continue to, affect our industry. New causes of Illinois Departmentaction and theories of Insurance (which is our global group-wide supervisor), the U.K. Prudential Regulatory Authoritydamages continue to be proposed in court actions and Financial Conduct Authority, the Bermuda Monetary Authorityby federal and the Office of Superintendent of Financial Institutions in Canada.state legislatures that continue to expand liability for insurers and their policyholders.

Hardy, a specialized Lloyd's of London (Lloyd's) underwriter, is also supervised by the Council of Lloyd's, which is the franchisor for all Lloyd's operations. The Council of Lloyd's has wide discretionary powers to regulate Lloyd's underwriting, such as establishing the capital requirements for syndicate participation. In addition, the annual business plansplan of each syndicate areis subject to the review and approval of the Lloyd's Franchise Board, which is responsible for business planning and monitoring for all syndicates.

The U.S. Federal Reserve,IAIS has recently adopted a Common Framework for the U.S. FederalSupervision of Internationally Active Insurance Office andGroups (ComFrame) which is focused on the National Associationeffective group-wide supervision of Insurance Commissioners (NAIC) are working with other global regulators to defineinternationally active insurance groups, such proposals. It is not currently clear to what extentas CNA. As part of ComFrame, the IAIS activities will affect us, as any final proposal would ultimately need to be legislated or regulated by each individual country or state.

There have also been definitive developments recently with respect to prudential insurance supervision.supervision unrelated to the IAIS activities. On September 22, 2017, the U.S. Treasury Department, the U.S. Trade Representative (USTR)

and the E.U.E. U. announced they had formally signed a covered agreement on Prudential Measures Regarding Insurance and Reinsurance (Covered(U.S.-E.U. Covered Agreement). The U.S.-E.U. Covered Agreement requires U.S. states to prospectively eliminate the requirement that domestic insurance companies must obtain collateral from E.U. reinsurance companies that are not licensed in their state (alien reinsurers) in order to obtain reserve credit under statutory accounting. In exchange, the E.U. will not impose local presence requirements on U.S. firms operating in the E.U., and effectively must defer to U.S. group capital regulation for these firms. TheOn December 18, 2018, the U.S. Treasury Department, the USTR, and USTR also released a U.S. policy statement clarifying their interpretation of the U.K. announced they formally signed the Bilateral Agreement on Prudential Measures Regarding Insurance and Reinsurance (U.S.-U.K. Covered Agreement). This Agreement has similar terms as the U.S.-E.U. Covered Agreement, in several key areas including, capital, group supervision and reinsurance.will become effective upon the U.K.'s exit from the E.U.

Because the Covered Agreement isthese covered agreements are not self-executing, U.S. state laws will need to be revised to change reinsurance collateral requirements to conform to the Covered Agreement. Before any such revision to state laws can be advanced, the NAIC must develop a new approach for determinationprovisions within each of the appropriate reserve credit under statutory accounting for E.U. based alien reinsurers.agreements. In addition, the NAIC is currently developing an approach to group capital regulation as the current U.S. regulatory regime is based on legal entity regulation. Both the reinsurance collateral requirement change and adoption of group capital regulation must be affectedeffected by the states within five years from the signing of the Covered Agreement,Agreements, or states risk federal preemption. We will monitor the modification of state laws and regulations in order to comply with the provisions of the Covered AgreementAgreements and assess its potential effects on our operations and prospects.

As of December 31, 2017,2019, we had approximately 6,3005,900 employees and have experienced satisfactory labor relations. We have never had work stoppages due to labor disputes.

We have comprehensive benefit plans for substantially all of our employees, including retirement plans,and savings plans, disability programs, group life programs and group health care programs. See Note I to the Consolidated Financial Statements included under Item 8 for further discussion of our benefit plans.

Our business faces many risks and uncertainties. These risks and uncertainties could lead to events or circumstances that have a material adverse effect on our results of operations, equity, business and insurer financial strength and corporate debt ratings. We have described below the most significant risks facing us.that we face. There may be additional risks that we do not yet know of or that we do not currently perceive to be as significant that may also affect our business. You should carefully consider and evaluate all of the information included in this report and any subsequent reports we may file with the SEC or make available to the public before investing in any securities we issue.

We maintain insurance reserves to cover our estimated ultimate unpaid liability for claim and claim adjustment expenses, including the estimated cost of the claims adjudication process, for reported and unreported claims. Insurance reserves are not an exact calculation of liability but instead are complex management estimates developed utilizing a variety of actuarial reserve estimation techniques as of a given reporting date. The reserve estimation process involves a high degree of judgment and variability and is subject to a number of factors which are highly uncertain. These variables can be affected by both changes in internal processes and external events. Key variables include claim severity, frequency of claims, claim severity, mortality, morbidity, discount rates, inflation, claim handling policies and procedures, case reserving approach, underwriting and pricing policies, changes in the legal and regulatory environment and the lag time between the occurrence of an insured event and the time of its ultimate settlement. Mortality is the relative incidence of death. Morbidity is the frequency and severity of injury, illness, sickness and diseases contracted.

There is generally a higher degree of variability in estimating required reserves for long-tail coverages, such as general liability and workers' compensation, as they require a relatively longer period of time for claims to be reported and settled. The impact of changes in inflation and medical costs are also more pronounced for long-tail coverages due to the longer settlement period. Certain risks and uncertainties associated with our insurance reserves are outlined in the Critical Accounting Estimates and the Reserves - Estimates and Uncertainties sections of MD&A in Item 7.

We are subject to the uncertain effects of emerging or potential claims and coverage issues that arise as industry practices and legal, judicial, social, economic and other environmental conditions change. These issues have had, and may continue to have, a negative effect on our business by either extending coverage beyond the original underwriting intent or by increasing the number or size of claims, resulting in further increases in our reserves. The effects of unforeseen emerging claim and coverage issues are extremely difficult to predict.

Our active life reserves for long term care policies are based on our best estimate assumptions as of December 31, 2015,September 30, 2019, due to ana reserve unlocking at that date. Key assumptions include morbidity, persistency (the percentage of policies remaining in force), discount rate and future premium rate increases. These assumptions, which are critical bases for our reserve estimates, are inherently uncertain. If actual experience varies from these assumptions or the future outlook for these assumptions changes, we may be required to increase our reserves. See the Life & Group

Estimating future experience for long term care policies is highly uncertain because the required projection period is very long and there is limited historical and industry data available to us, as only a small portionadequacy of the long term care policiesreserves is contingent upon actual experience and our future expectations related to these key assumptions. If actual or expected future experience differs from these assumptions, the reserves may not be adequate, requiring us to add reserves. The required increase in reserves would be recorded as a charge against our earnings in the period in which have been writtenreserves are determined to date are in claims paying status. be insufficient. These charges could be substantial.

Morbidity and persistency trends,experience, inclusive of mortality, can be volatile and may be negatively affected by many factors including, but not limited to, policyholder behavior, judicial decisions regarding policy terms, socioeconomic factors, cost of care inflation, changes in health trends and advances in medical care.

A prolonged period during which interest rates remain at levels lower than those anticipated in our reserving would result in shortfalls in investment income on assets supporting our obligations under long term care policies, which may require changes to our reserves. This risk is more significant for our long term care products because the long potential duration of the policy obligations exceeds the duration of the supporting investment assets. Further, changes to the corporate tax codeInternal Revenue Code may also affect the rate at which we discount our reserves. In addition, we may not receive regulatory approval for the level of premium rate increases we request. Any adverse deviation between the level of future premium rate increases approved and the level included in our reserving assumptions may require an increase to our reserves.

Catastrophe losses are an inevitable part of our business. Various events can cause catastrophe losses. These events can be natural or man-made, and may include hurricanes, windstorms, earthquakes, hail, severe winter weather, fires, floods, riots, strikes, civil commotion, cyber attacks, pandemics and acts of terrorism. The frequency and severity of these catastrophe events are inherently unpredictable. In addition, longer-term natural catastrophe trends may be changing and new types of catastrophe losses may be developing due to climate change, a phenomenon that has been associated with extreme weather events linked to rising temperatures and includes effects on global weather patterns, greenhouse gases, sea, land and air temperatures, sea levels, rain, hail and snow.

The extent of our losses from catastrophes is a function of the total amount of our insured exposures in the affected areas, the frequency and severity of the events themselves, the level of reinsurance assumed and ceded,coverage, reinsurance reinstatement premiums and state residual market assessments, if any. It can take a long time for the ultimate cost of any catastrophe losses to us to be finally determined, as a multitude of factors contribute to such costs, including evaluation of general liability and pollution exposures, infrastructure disruption, business interruption and reinsurance collectibility.

Reinsurance coverage for terrorism events is provided only in limited circumstances, especially in regard to “unconventional” terrorism acts, such as nuclear, biological, chemical or radiological attacks. Our principal reinsurance protection against these large-scale terrorist attacks is the coverage currently provided through TRIPRA through December 31, 2027. However, such coverage is subject to a mandatory deductible and other limitations. It is also possible that future legislation could change or eliminate the program, which could adversely affect our business by increasing our exposure to terrorism losses, or by lowering our business volume through efforts to avoid that exposure. For a further discussion of TRIPRA, see Part II, Item 7, MD&A - Catastrophes and Related Reinsurance.

As a result of the items discussed above, catastrophe losses are particularly difficult to estimate. Additionally, catastrophic events could cause us to exhaust our available reinsurance limits and could adversely affect the cost and availability of reinsurance.

We use various modeling techniques and data analytics (e.g., scenarios, predictive, stochastic and/or forecasting) to analyze and estimate exposures, loss trends and other risks associated with our assets and liabilities. This includes both proprietary and third party modeled outputs and related analyses to assist us in decision-making related to underwriting, pricing, capital allocation, reserving, investing, reinsurance and catastrophe risk, among other things. We incorporate numerous assumptions and forecasts about the future level and variability of policyholder behavior, loss frequency and severity, interest rates, equity markets, inflation, capital requirements, and currency exchange rates, among others. The modeled outputs and related analyses from both proprietary models and third parties are subject to various assumptions, uncertainties, model design errors and the inherent limitations of any statistical analysis, including those arising from the use of historical internal and industry data and assumptions.analysis.

In addition, the effectiveness of any model can be degraded by operational risks including, but not limited to, the improper use of the model, including input errors, data errors and human error. As a result, actual results may differ materially from our modeled results. The profitability and financial condition of the Company substantially depends on the extent to which our actual experience is consistent with assumptions we use in our models and ultimate model outputs. If, based upon these models or other factors, we misprice our products or fail to appropriately estimate the risks we are exposed to, our business, financial condition, results of operations or liquidity may be materially adversely affected.

All aspects of the insurance industry are highly competitive and we must continuously allocate resources to refine and improve our insurance products and services to remain competitive. We compete with a large number of stock and mutual insurance companies and other entities, some of which may be larger or have greater financial or other resources than we do, for both distributors and customers. This includes agents, brokers and brokersmanaging general underwriters who may increasingly compete with us to the extent that markets continue to provide them with direct access to providers of capital seeking exposure to insurance risk. Insurers compete on the basis of many factors, including products, price, services, ratings and financial strength. The competitor landscape has evolved substantially in recent years, with significant consolidation and new market entrants, resulting in increased pressures on our ability to remain competitive, particularly in implementingobtaining pricing that is both attractive to our customer base and risk-appropriate to us.

In addition, agents and brokers, technology companies, or other third parties may create alternate distribution channels for commercial business that may adversely impact product differentiation and pricing. For example, they may create a digitally enabled distribution channel that may adversely impact our competitive position. Our efforts or the efforts of agents and brokers with respect to new products or alternate distribution channels, as well as changes in the way agents and brokers utilize greater levels of data and technology, could adversely impact our business relationship with independent agents and brokers who currently market our products, resulting in a lower volume and/or profitability of business generated from these sources.

WeA primary reason we purchase reinsurance is to help manage our exposure to risk. Under our ceded reinsurance arrangements, another insurer assumes a specified portion of our exposure in exchange for a specified portion of policy premiums. Market conditions determine the availability and cost of the reinsurance protection we purchase, which affects the level of our business and profitability, as well as the level and types of risk we retain. If we are unable to obtain sufficient reinsurance at a cost or on terms and conditions we deem acceptable, we may have increased exposure to risk. Alternatively, we may be unwilling to bear the increased risk and would reduce the level of our underwriting commitments.

We have significant amounts recoverable from reinsurers which are reported as receivables on our Consolidated Balance Sheets and are estimated in a manner consistent with claim and claim adjustment expense reserves or future policy benefit reserves. The ceding of insurance does not, however, discharge our primary liability for claims. As a result, we are subject to credit risk relating to our ability to recover amounts due from reinsurers. Certain of our reinsurance carriers have experiencedcould experience credit downgrades by rating agencies within the term of our contractual relationship, which indicateswould indicate an increase in the likelihood that we willwould not be able to recover amounts due. In addition, reinsurers could dispute amounts which we believe are due to us. If the amounts duecollected from reinsurers, that we are able to collectincluding any collateral, are less than the amountamounts recorded by us, with respect to such amounts due, our net incurred losses will be higher.

A portion of our business is written under deductible policies. Under these policies, we are obligated to pay the related insurance claims and are reimbursed by the policyholder to the extent of the deductible, which may be significant.

Our investment portfolio is exposed to various risks, such as interest rate, credit spread, issuer default, equity prices and foreign currency, which are unpredictable. Financial markets are highly sensitive to changes in economic conditions, monetary policies, tax policies, domestic and international geopolitical issues and many other factors. Changes in financial markets including fluctuations in interest rates, credit, equity prices and foreign currency prices and many other factors beyond our control can adversely affect the value of our investments, the realization of investment income and the rate at which we discount certain liabilities.

We have significant holdings in fixed incomematurity investments that are sensitive to changes in interest rates. A decline in interest rates may reduce the returns earned on new fixed incomematurity investments, thereby reducing our net investment income, while an increase in interest rates may reduce the value of our existing fixed maturity investments, which could reduce our net unrealized gains included in Accumulated other comprehensive income investments.(AOCI). The value of our fixed incomematurity investments is also subject to risk that certain investments may default or become impaired due to deterioration in the financial condition of issuers of the investments we hold or in the underlying collateral of the security. Any such impairments which we deem to be other-than-temporary would result in a charge to our earnings.

In addition, we invest a portion of our assets in limited partnerships which are subject to greater market volatility than our fixed incomematurity investments. Limited partnership investments generally provide a lower level of liquidity than fixed maturity or equity investments which may also limit our ability to withdraw assets.funds from these investments. The timing and amount of income or losses on such investments is inherently variable and can contribute to volatility in reported earnings.

Further, we hold a portfolio of commercial mortgage loans. We are subject to risk related to the recoverability of loan balances, which is influenced by declines in the estimated cash flows from underlying property leases, fair value of collateral, refinancing risk and the creditworthiness of tenants of credit tenant loan properties, where lease payments directly service the loan. Collecting amounts from borrowers that are less than the amounts recorded would result in a charge to our earnings.

As a result of these factors, we may not earn an adequate return on our investments, may be required to write downwrite-down the value of our investments and may incur losses on the disposition of our investments.investments all of which could materially adversely affect our results of operations.

The foregoing risks relating to disruption of service, interruption of operations and data loss could expose us to monetary and reputational damages. In addition, potentialPotential exposures include substantially increased compliance costs and required computer system upgrades and security-related investments.

A significant breach of our data security infrastructure may result from actions by our employees, vendors, third-party administrators or by unknown third parties. Such a breach could affect our data framework or cause a failure to protect the personal information of our customers, claimants or employees, or sensitive and confidential information regarding our business and may result in operational impairments and financial losses, as well as significant harm to our reputation.

The breach of confidential information also could give rise to legal liability and regulatory action under data protection and privacy laws, as well as evolving regulation in this regard, including the recently issued New York Department of Financial Services cyber regulation.regard. Any such legal or regulatory action could have a material adverse effect on our operations.

We may incur losses which arise from employees or third party service providers engaging in intentional misconduct, fraud, errors and omissions, failure to comply with internal guidelines, including with respect to underwriting authority, or failure to comply with regulatory requirements. Our controls may not be able to detect all possible circumstances of employee and third party service provider non-compliant activity and the internal structures in place to prevent this activity may not be effective in all cases. Any losses relating to such non-compliant activity could adversely affect our results of operations.

In the event that one or more of our vendors suffers a bankruptcy, is sold to another entity, sustains a significant business interruption or otherwise becomes unable to continue to provide products or services at the requisite level, we may be adversely affected. We may suffer operational impairments and financial losses associated with transferring business to a new vendor, assisting a vendor with rectifying operational difficulties, failure by vendors to properly perform service functions or assuming previously outsourced operations ourselves. Our inability to provide for appropriate servicing if a vendor becomes unable to fulfill its contractual obligations to us, either through transitioning to another service provider temporarily or permanently or assuming servicing internally, may have a materially adverse effect on our operations.

The successful execution of our business plan depends on our ability to attract and retain qualified talent. Due to the intense competition in our industry and from businesses outside the industry for qualified employees, withespecially those in key positions and those possessing highly specialized knowledge and industry experience in areas such as underwriting, data and analytics and technology, we may encounter obstacles to our ability to attract and retain such employees, which could materially adversely affect our results of operations.

Insurance companies such as ours are subject to capital adequacy standards set by regulators to help identify companies that merit further regulatory attention. TheseIn the U.S., these standards apply specified risk factors to various asset, premium and reserve components of our legal entity statutory basis of accounting financial statements. Current rules, including those promulgated by insurance regulators and specialized markets, such as Lloyd's, require companies to maintain statutory capital and surplus at a specified minimum level determined using the applicable

jurisdiction's regulatory capital adequacy formula. If we do not meet these minimum requirements, we may be restricted or prohibited from operating our business in the applicable jurisdictions and specialized markets. If we are required to record a material charge against earnings in connection with a change in estimated insurance reserves, the occurrence of a catastrophic event, or if we incur significant losses related to our investment portfolio, which severely deterioratedeteriorates our capital position, we may violate these minimum capital adequacy requirements unless we are able to raise sufficient additional capital. We may be limited in our ability to raise significant amounts of capital on favorable terms or at all.

Globally, insurance regulators are working cooperatively to developThe IAIS recently adopted a common framework for the supervision of internationally active insurance groups. Finalizationgroups and continues to develop a group basis Insurance Capital Standard (ICS). The NAIC is also developing a group capital standard that is intended to be comparable to the ICS. The development and adoption of this frameworkthese capital standards could increase our prescribed capital requirement, the level at which regulatory scrutiny intensifies, as well as significantly increase our cost of regulatory compliance.

We are a holding company and are dependent upon dividends, loans and other sources of cash from our subsidiaries in order to meet our obligations. Ordinary dividend payments, or dividends that do not require prior approval by the insurance subsidiaries' domiciliary insurance regulator, are generally limited to amounts determined by formulas that vary by jurisdiction. If we are restricted from paying or receiving intercompany dividends, by regulatory rule or otherwise, we may not be able to fund our corporate obligations and debt service requirements or pay our stockholders dividends from available cash. As a result, we would need to look to other sources of capital which may be more expensive or may not be available at all.

Ratings are an important factor in establishing the competitive position of insurance companies. Our insurance company subsidiaries, as well as our public debt, are rated by rating agencies, including, A.M. Best Company (A.M. Best), Moody's Investors Service, Inc. (Moody's) and Standard & Poor's (S&P). Ratings reflect the rating agency's opinions of an insurance company's or insurance holding company's financial strength, capital adequacy, enterprise risk management practices, operating performance, strategic position and ability to meet its obligations to policyholders and debt holders.

The rating agencies may take action to lower our ratings in the future as a result of any significant financial loss or possible changes in the methodology or criteria applied by the rating agencies. The severity of the impact on our business is dependent on the level of downgrade and, for certain products, which rating agency takes the rating action. Among the adverse effects in the event of such downgrades would be the inability to obtain a material volume of business from certain major insurance brokers, the inability to sell a material volume of our insurance products to certain markets and the required collateralization of certain future payment obligations or reserves.

In addition, it is possible that a significant lowering of the corporate debt ratings of Loews by certain of the rating agencies could result in an adverse affecteffect on our ratings, independent of any change in our circumstances.

The insurance industry is subject to comprehensive and detailed regulation and supervision. Most insurance regulations are designed to protect the interests of our policyholders and third-party claimants, rather than our

These rules and regulations relate to, among other things, the standards of solvency (including risk-based capital measures), government-supported backstops for certain catastrophic events (including terrorism), investment restrictions, accounting and reporting methodology, establishment of reserves and potential assessments of funds to settle covered claims against impaired, insolvent or failed private or quasi-governmental insurers.

Regulatory powers also extend to premium rate regulations which require that rates not be excessive, inadequate or unfairly discriminatory. State jurisdictions ensure compliance with such regulations through market conduct exams, which may result in losses to the extent non-compliance is ascertained, either as a result of failure to document transactions properly or failure to comply with internal guidelines, or otherwise. The jurisdictions in which we do business may also require us to provide coverage to persons whom we would not otherwise consider eligible or restrict us from withdrawing from unprofitable lines of business or unprofitable market areas. Each jurisdiction dictates the types of insurance and the level of coverage that must be provided to such involuntary risks. Our share of these involuntary risks is mandatory and generally a function of our respective share of the voluntary market by line of insurance in each jurisdiction.

None.

Our Chicago location housesWe lease our principal executive offices. We lease office spaceoffices in various citiesChicago, Illinois, as well as other property and casualty insurance offices totaling approximately 1.3 million square feet throughout the United StatesU.S.  We also lease offices in Canada, the U.K., Belgium, Denmark, France, Germany, Italy, Luxembourg and the Netherlands, primarily for branch and insurance business operations in other countries. The following table sets forth certain information with respect to our principal office locations.those locations, totaling approximately 130 thousand square feet.

Information on our legal proceedings is set forth in Note F to the Consolidated Financial Statements included under Item 8.

Not applicable.

Our common stock is listed on the New York Stock Exchange and the Chicago Stock Exchange under the symbol CNA.

Our Board of Directors has approved an authorization to purchase, in the open market or through privately negotiated transactions, our outstanding common stock, as our management deems appropriate. No repurchases were made in 2017 or 2016.

The table below shows the high and low closing prices fordetails repurchases of our common stock based onmade during the New York Stock Exchange Composite Transactions, as well as the dividends declared on our common stock.three months ended December 31, 2019.

The following graph compares the five-year total return of our common stock, the Standard & Poor's 500 (S&P 500) Index and the S&P 500 Property & Casualty Insurance Index. The graph assumes that the value of the investment in our common stock and each index was $100 at the base period, January 1, 2013,2015, and that dividends, if any, were reinvested.reinvested in the stock or index.

The following table presents selected consolidated financial data. The table should be read in conjunction with Item 7 Management's Discussion and Analysis of Financial Condition and Results of Operations and Item 8 Financial Statements and Supplementary Data of this Form 10-K.

The following discussion should be read in conjunction with Item 1A Risk Factors, Item 6 Selected Financial Data and Item 8 Financial Statements and Supplementary Data of this Form 10-K.

The preparation of Consolidated Financial Statements in conformity with accounting principles generally accepted in the United States of America (GAAP)GAAP requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the Consolidated Financial Statements and the amount of revenues and expenses reported during the period. Actual results may differ from those estimates.

Our Consolidated Financial Statements and accompanying notes have been prepared in accordance with GAAP applied on a consistent basis. We continually evaluate the accounting policies and estimates used to prepare the Consolidated Financial Statements. In general, our estimates are based on historical experience, evaluation of current trends, information from third-party professionals and various other assumptions that are believed to be reasonable under the known facts and circumstances.

The accounting estimates discussed below are considered by us to be critical to an understanding of our Consolidated Financial Statements as their application places the most significant demands on our judgment. Note A to the Consolidated Financial Statements included under Item 8 should be read in conjunction with this section to assist with obtaining an understanding of the underlying accounting policies related to these estimates. Due to the inherent uncertainties involved with these types of judgments, actual results could differ significantly from our estimates and may have a material adverse impact on our results of operations, equity, business, and insurer financial strength and corporate debt ratings.

Insurance reserves are established for both short and long-duration insurance contracts. Short-duration contracts are primarily related to property and casualty insurance policies where the reserving process is based on actuarial estimates of the amount of loss, including amounts for known and unknown claims. Long-duration contracts are primarily related to long term care policies and are estimated using actuarial estimates about morbidity and persistency as well as assumptions about expected investment returns and future premium rate increases. The reserve for unearned premiums on property and casualty contracts represents the portion of premiums written related to the unexpired terms of coverage. The reserving process is discussed in further detail in the Reserves-Estimates and Uncertainties section below.

Future policy benefit reserves for our long term care policies are based on certain assumptions, including morbidity, persistency, inclusive of mortality, discount rates and future premium rate increases. The adequacy of the reserves is contingent upon actual experience and our future expectations related to these key assumptions. If actual or expected future experience differs from these assumptions, the reserves may not be adequate, requiring us to add to reserves.

A prolonged period during which interest rates remain at levels lower than those anticipated in our reserving discount rate assumption could result in shortfalls in investment income on assets supporting our obligations under long term care policies, which may also require an increase to our reserves. In addition, we may not receive regulatory approval for the premium rate increases we request.

These changes to our reserves could materially adversely impact our results of operations and equity. The reserving process is discussed in further detail in the Reserves - Estimates and Uncertainties section below.

We account for income taxes under the asset and liability method. Under this method, deferred income taxes are recognized for temporary differences between the financial statement and tax return basis of assets and liabilities. Any resulting future tax benefits are recognized to the extent that realization of such benefits is more likely than not, and a valuation allowance is established for any portion of a deferred tax asset that management believes will not be realized. The assessment of the need for a valuation allowance requires management to make estimates and assumptions about future earnings, reversal of existing temporary differences and available tax planning strategies. If actual experience differs from these estimates and assumptions, the recorded deferred tax asset may not be fully realized resulting in an increase to income tax expense in our results of operations. In addition, the ability to record deferred tax assets in the future could be limited, resulting in a higher effective tax rate in that future period.

The level of claim reserves we maintain represents our best estimate, as of a particular point in time, of what the ultimate settlement and administration of claims will cost based on our assessment of facts and circumstances known at that time. Reserves are not an exact calculation of liability but instead are complex estimates that we derive, generally utilizing a variety of actuarial reserve estimation techniques, from numerous assumptions and expectations about future events, both internal and external, many of which are highly uncertain. As noted below, we review our reserves for each segment of our business periodically, and any such review could result in the need to increase reserves in amounts which could be material and could adversely affect our results of operations, equity, business and insurer financial strength and corporate debt ratings. Further information on reserves is provided in Note E to the Consolidated Financial Statements included under Item 8.

We maintain loss reserves to cover our estimated ultimate unpaid liability for claim and claim adjustment expenses, including the estimated cost of the claims adjudication process, for claims that have been reported but not yet settled (case reserves) and claims that have been incurred but not reported (IBNR). IBNR includes a provision for development on known cases as well as a provision for late reported incurred claims. Claim and claim adjustment expense reserves are reflected as liabilities and are included on the Consolidated Balance Sheets under the heading “Insurance Reserves.” Adjustments to prior year reserve estimates, if necessary, are reflected in results of operations in the period that the need for such adjustments is determined. The carried case and IBNR reserves as of each balance sheet date are provided in the Segment Results section of this MD&A and in Note E to the Consolidated Financial Statements included under Item 8.

As discussed in the Risk Factors discussion within Item 1A, there is a risk that our recorded reserves are insufficient to cover our estimated ultimate unpaid liability for claims and claim adjustment expenses. Unforeseen emerging or potential claims and coverage issues are difficult to predict and could materially adversely affect the adequacy of our claim and claim adjustment expense reserves and could lead to future reserve additions.

In addition, our property and casualty insurance subsidiaries also have actual and potential exposures related to A&EP claims, which could result in material losses. To mitigate the risks posed by our exposure to A&EP claims and claim adjustment expenses, we completed a transaction with NICO under which substantially all of our legacy A&EP liabilities were ceded to NICO effective January 1, 2010. See Note E to the Consolidated Financial Statements included under Item 8 for further discussion about the transaction with NICO, its impact on our results of operations, and the deferred retroactive reinsurance gain.gain and the amount of remaining reinsurance limit.

In developing claim and claim adjustment expense (“loss”(loss or “losses”)losses) reserve estimates, our actuaries perform detailed reserve analyses that are staggered throughout the year. The data is organized at a reserve group level. A reserve group can be a line of business covering a subset of insureds such as commercial automobile liability for small or middle market customers it can encompass several lines of business provided to a specific set of customers such as aging services, or it can be a particular type of claim such as construction defect. Every reserve group is reviewed at least once during the year.year, but most are reviewed more frequently. The analyses generally review losses gross of ceded reinsurance and apply the ceded reinsurance terms to the gross estimates to establish estimates net of reinsurance. In addition to the detailed analyses, we review actual loss emergence for all products each quarter.

Most of our business can be characterized as long-tail. For long-tail business, it will generally be several years between the time the business is written and the time when all claims are settled. Our long-tail exposures include commercial automobile liability, workers' compensation, general liability, medical professional liability, other professional liability and management liability coverages, assumed reinsurance run-off and products liability. Short-tail exposures include property, commercial automobile physical damage, marine, surety and warranty. Specialty, Commercial and International contain both long-tail and short-tail exposures. Corporate & Other contains run-off long-tail exposures.

Various methods are used to project ultimate losses for both long-tail and short-tail exposures.

The paid development method estimates ultimate losses by reviewing paid loss patterns and applying them to accident or policy years with further expected changes in paid losses. Selection of the paid loss pattern may require

consideration of several factors, including the impact of inflation on claimsclaim costs, the rate at which claims professionals make claim payments and close claims, the impact of judicial decisions, the impact of underwriting changes, the impact of large claim payments and other factors. Claim cost inflation itself may require evaluation of changes in the cost of repairing or replacing property, changes in the cost of medical care, changes in the cost of wage replacement, judicial decisions, legislative changes and other factors. Because this method assumes that losses are paid at a consistent rate, changes in any of these factors can affect the results. Since the method does not rely on case reserves, it is not directly influenced by changes in their adequacy.

For many reserve groups, paid loss data for recent periods may be too immature or erratic for accurate predictions. This situation often exists for long-tail exposures. In addition, changes in the factors described above may result in inconsistent payment patterns. Finally, estimating the paid loss pattern subsequent to the most mature point available in the data analyzed often involves considerable uncertainty for long-tail products such as workers' compensation.

The incurred development method is similar to the paid development method, but it uses case incurred losses instead of paid losses.  Since the method uses more data (case reserves in addition to paid losses) than the paid development method, the incurred development patterns may be less variable than paid patterns. However, selection of the incurred loss pattern typically requires analysis of all of the same factors described above. In addition, the inclusion of case reserves can lead to distortions if changes in case reserving practices have taken place, and the use of case incurred losses may not eliminate the issues associated with estimating the incurred loss pattern subsequent to the most mature point available.

The loss ratio method multiplies earned premiums by an expected loss ratio to produce ultimate loss estimates for each accident or policy year. This method may be useful for immature accident or policy periods or if loss development patterns are inconsistent, losses emerge very slowly or there is relatively little loss history from which to estimate future losses. The selection of the expected loss ratio typically requires analysis of loss ratios from earlier accident or policy years or pricing studies and analysis of inflationary trends, frequency trends, rate changes, underwriting changes and other applicable factors.

The Bornhuetter-Ferguson method using paid loss is a combination of the paid development method and the loss ratio method. This method normally determines expected loss ratios similar to the approach used to estimate the expected loss ratio for the loss ratio method and typically requires analysis of the same factors described above. This method assumes that future losses will develop at the expected loss ratio level. The percent of paid loss to ultimate loss implied from the paid development method is used to determine what percentage of ultimate loss is yet to be paid. The use of the pattern from the paid development method typically requires consideration of the same factors listed in the description of the paid development method. The estimate of losses yet to be paid is added to current paid losses to estimate the ultimate loss for each year. For long-tail lines, this method will react very slowly if actual ultimate loss ratios are different from expectations due to changes not accounted for by the expected loss ratio calculation.

The Bornhuetter-Ferguson method using incurred loss is similar to the Bornhuetter-Ferguson method using paid loss except that it uses case incurred losses. The use of case incurred losses instead of paid losses can result in development patterns that are less variable than paid patterns. However, the inclusion of case reserves can lead to distortions if changes in case reserving have taken place, and the method typically requires analysis of the same factors that need to be reviewed for the loss ratio and incurred development methods.

The frequency times severity method multiplies a projected number of ultimate claims by an estimated ultimate average loss for each accident or policy year to produce ultimate loss estimates. Since projections of the ultimate number of claims are often less variable than projections of ultimate loss, this method can provide more reliable results for reserve groups where loss development patterns are inconsistent or too variable to be relied on exclusively. In addition, this method can more directly account for changes in coverage that affect the number and size of claims. However, this method can be difficult to apply to situations where very large claims or a substantial number of unusual claims result in volatile average claim sizes. Projecting the ultimate number of claims may require analysis of several factors, including the rate at which policyholders report claims to us, the impact of judicial decisions, the impact of underwriting changes and other factors. Estimating the ultimate average loss may require analysis of the impact of large losses and claim cost trends based on changes in the cost of repairing or replacing

property, changes in the cost of medical care, changes in the cost of wage replacement, judicial decisions, legislative changes and other factors.

Stochastic modeling produces a range of possible outcomes based on varying assumptions related to the particular reserve group being modeled. For some reserve groups, we use models which rely on historical development patterns at an aggregate level, while other reserve groups are modeled using individual claim variability assumptions supplied by the claims department. In either case, multiple simulations using varying assumptions are run and the results are analyzed to produce a range of potential outcomes. The results will typically include a mean and percentiles of the possible reserve distribution which aid in the selection of a point estimate.

For many exposures, especially those that can be considered long-tail, a particular accident or policy year may not have a sufficient volume of paid losses to produce a statistically reliable estimate of ultimate losses. In such a case, our actuaries typically assign more weight to the incurred development method than to the paid development method. As claims continue to settle and the volume of paid loss increases, the actuaries may assign additional weight to the paid development method.  For most of our products, even the incurred losses for accident or policy years that are early in the claim settlement process will not be of sufficient volume to produce a reliable estimate of ultimate losses. In these cases, we may not assign much, if any, weight to the paid and incurred development methods. We may use the loss ratio, Bornhuetter-Ferguson and/or frequency times severity methods.  For short-tail exposures, the paid and incurred development methods can often be relied on sooner, primarily because our history includes a sufficient number of years to cover the entire period over which paid and incurred losses are expected to change. However, we may also use the loss ratio, Bornhuetter-Ferguson and/or frequency times severity methods for short-tail exposures.

For other more complex reserve groups where the above methods may not produce reliable indications, we use additional methods tailored to the characteristics of the specific situation.

The reserve analyses performed by our actuaries result in point estimates. Each quarter, the results of the detailed reserve reviews are summarized and discussed with senior management to determine themanagement's best estimate of reserves. Senior management considers many factors in making this decision. Our recorded reserves reflect our best estimate as of a particular point in time based upon known facts and circumstances, consideration of the factors cited above and our judgment. The carried reserve differs from the actuarial point estimate as discussed further below.

The key assumptions fundamental to the reserving process are often different for various reserve groups and accident or policy years. Some of these assumptions are explicit assumptions that are required of a particular method, but most of the assumptions are implicit and cannot be precisely quantified. An example of an explicit assumption is the pattern employed in the paid development method. However, the assumed pattern is itself based on several implicit assumptions such as the impact of inflation on medical costs and the rate at which claim professionals close claims. As a result, the effect on reserve estimates of a particular change in assumptions typically cannot be specifically quantified, and changes in these assumptions cannot be tracked over time.

Our recorded reserves are management's best estimate. In order to provide an indication of the variability associated with our net reserves, the following discussion provides a sensitivity analysis that shows the approximate estimated impact of variations in significant factors affecting our reserve estimates for particular types of business. These significant factors are the ones that we believe could most likely materially affect the reserves. This discussion covers the major types of business for which we believe a material deviation to our reserves is reasonably possible. There can be no assurance that actual experience will be consistent with the current assumptions or with the variation indicated by the discussion. In addition, there can be no assurance that other factors and assumptions will not have a material impact on our reserves.

The three areas for which we believe a significant deviation to our net reserves is reasonably possible are (i) professional liability, management liability and surety products; (ii) workers' compensation; and (iii) general liability.

Professional liability, management liability and surety products include U.S. professional liability coverages provided to various professional firms, including architects, real estate agents, small and mid-sized accounting firms, law firms and other professional firms. They also include directors and officers (D&O), employment practices, fiduciary, fidelity and surety coverages, as well as insurance products serving the healthcare delivery system.and medical liability. The most significant factor affecting reserve estimates for these liability coverages is claim severity. Claim severity is driven by the cost of medical care, the cost of wage replacement, legal fees, judicial decisions, legislative changes and other factors. Underwriting and claim handling decisions, such as the classes of business written and individual claim settlement decisions, can also affect claim severity. If the estimated claim severity increases by 9%, we estimate that net reserves would increase by approximately $450$400 million. If the estimated claim severity decreases by 3%, we estimate that net reserves would decrease by approximately $150 million. Our net reserves for these products were approximately $5.0$4.4 billion as of December 31, 2017.2019.

For workers' compensation, since many years will pass from the time the business is written until all claim payments have been made, the most significant factor affecting workers' compensation reserve estimates is claim cost inflation on claim payments. Workers' compensation claim cost inflation is driven by the cost of medical care, the cost of wage replacement, expected claimant lifetimes, judicial decisions, legislative changes and other factors. If estimated workers' compensation claim cost inflation increases by 100 basis points for the entire period over which claim payments will be made, we estimate that our net reserves would increase by approximately $350 million. If estimated workers' compensation claim cost inflation decreases by 100 basis points for the entire period over which claim payments will be made, we estimate that our net reserves would decrease by approximately $350 million. Our net reserves for workers' compensation were approximately $4.0 billion as of December 31, 2017.2019.

For general liability, the most significant factor affecting reserve estimates is claim severity. Claim severity is driven by changes in the cost of repairing or replacing property, the cost of medical care, the cost of wage replacement, judicial decisions, legislation and other factors. If the estimated claim severity for general liability increases by 6%, we estimate that our net reserves would increase by approximately $200 million. If the estimated claim severity for general liability decreases by 3%, we estimate that our net reserves would decrease by approximately $100 million. Our net reserves for general liability were approximately $3.3$3.4 billion as of December 31, 2017.2019.

Given the factors described above, it is not possible to quantify precisely the ultimate exposure represented by claims and related litigation. As a result, we regularly review the adequacy of our reserves and reassess our reserve estimates as historical loss experience develops, additional claims are reported and settled and additional information becomes available in subsequent periods. In reviewing our reserve estimates, we make adjustments in the period that the need for such adjustments is determined. These reviews have resulted in our identification of information and trends that have caused us to change our reserves in prior periods and could lead to our identification of a need for additional material increases or decreases in claim and claim adjustment expense reserves, which could materially affect our results of operations, equity, business and insurer financial strength and corporate debt ratings positively or negatively. See discussion within Note E to the Consolidated Financial Statements included under Item 8 for additional information about reserve development and the Ratings section of this MD&A for further information regarding our financial strength and corporate debt ratings.

Our Life & Group segment includes our run-off long term care business as well as structured settlement obligations not funded by annuities related to certain property and casualty claimants. Long term care policies provide benefits for nursing homes, assisted living facilities and home health care subject to various daily and lifetime caps. Generally, policyholders must continue to make periodic premium payments to keep the policy in force and we have the ability to increase policy premiums, subject to state regulatory approval.

We maintain both claim and claim adjustment expense reserves as well as future policy benefit reserves for policyholder benefits for our Life & Group segment. Claim and claim adjustment expense reserves consist of estimated reserves for long term care policyholders that are currently receiving benefits, including claims that have

Future policy benefit reserves represent the active life reserves related to our long term care policies andwhich are the present value of expected future benefit payments and expenses less expected future premium. The determination of these reserves is fundamental to our financial results and requires management to make estimates and assumptions about expected investment and policyholder experience over the life of the contract. The assumptions used to determine the active life reserves were unlocked as of December 31, 2015 in connection with the recognition of a premium deficiency. Since many of these contracts may be in force for several decades, these assumptions are subject to significant estimation risk.

Prior to September 30, 2019, the active life reserves for long term care were based on the actuarial best estimate assumptions established at December 31, 20172015 as a result of a reserve unlocking in the fourth quarter of 2015. The September 30, 2018 GPV indicated our recordedthe carried reserves included a margin of approximately $246$182 million. The September 30, 2019 GPV indicated a premium deficiency of $216 million and future policyholder benefit reserves at that date were increased accordingly. As a result, the long term care active life reserves carried as of September 30, 2019 represent management's best estimate assumptions at that date with no margin for adverse deviation. A summary of the changes inas a result of the estimated reserve margin2019 GPV is presented in the table below:

The decreasepremium deficiency was primarily driven by changes in thediscount rate assumptions driven by lower expected reinvestment rates, contemplating both near-term market indications and long-term normative assumptions. The premium deficiency was also adversely affected by changes in persistency assumptions, primarily from lower projected active life mortality rates. Recognition of margin in 2017 was driven byearnings subsequent to the reduction in2018 GPV also contributed to the Federal corporate income tax rate enacted on December 22, 2017 which reduced the tax equivalent yield on the tax exempt municipal bonds in the investment portfolio supporting the long term care liabilities. A continuation of the low interest rate environment also drove a reduction in the discount rate assumptions.premium deficiency. These unfavorable drivers were mostlypartially offset by favorable changes

Catastrophes are an inherent risk of the property and casualty insurance business and have contributed to material period-to-period fluctuations in our results of operations and/or equity. We reported catastrophe losses, net of reinsurance, of $179 million and $252 million for the years ended December 31, 2019 and 2018. Net catastrophe losses for the year ended December 31, 2019 related primarily to U.S. weather related events. Net catastrophe losses for the year ended December 31, 2018 included $88 million related to Hurricane Michael, $47 million related to the California wildfires and $33 million related to Hurricane Florence. The remaining net catastrophe losses in 2018 resulted primarily from U.S. weather related events.

We generally seek to manage our exposure to catastrophes through the table below are after considerationpurchase of the existing margin.

The Company purchasesWe purchased corporate catastrophe excess-of-loss treaty reinsurance covering itsour U.S. states and territories and Canadian property exposures underwritten in our North American and non-Lloyds European companies. Exposures underwritten through Hardy are excluded. The treaty has a term of January 1, 20182019 to December 31, 2018.May 1, 2020. The 20182019 treaty provides coverage for the accumulation of losses from catastrophe occurrences above the Company’sour per occurrence retention of $250 million up to $1.0 billion, with 10% co-participation on the first $650 million above the retention and 20% co-participation on the top $100 million layer.billion. Losses stemming from terrorism events are covered unless they are due to a nuclear, biological or chemical attack. All layers of the treaty provide for one full reinstatement.

The CompanyWe also purchasespurchased corporate WorkersWorkers' Compensation catastrophe excess-of-loss treaty reinsurance for the period January 1, 20182020 to December 31, 2018January 1, 2021 providing $275 million of coverage for the accumulation of covered losses related to natural catastrophes above the Companyour retention of $25 million. The treaty also provides $475 million of coverage for the accumulation of covered losses related to terrorism events above the Companyour retention of $25 million. Of this $475 million in Terrorism coverage, $200 million is provided for nuclear, biological chemical and radiation events. One full reinstatement is available for the first $275 million above the retention, regardless of the covered peril. The CompanyWe also purchasespurchased a targeted facultative facility to address exposure accumulations in specific peak Terrorism zones.

Core income increased $95$134 million in 20172019 as compared to 2016.with 2018. Core income for our Property & Casualty Operations declined $23increased approximately $223 million primarily due to higher net investment income driven by higher net catastrophe losses partially offset by improved non-catastrophelimited partnership and common stock returns and favorable current accident year underwriting results. Net catastrophe losses were $259results partially offset by lower favorable net prior period loss reserve development in the current year. Core results for our Life & Group segment decreased $152 million after tax in 2017driven by a $170 million charge related to recognition of a premium deficiency as compared to $111 million after tax in 2016.a result of the third quarter 2019 GPV. Core loss for our operations outside of PropertyCorporate & Casualty OperationsOther segment improved $118approximately $63 million driven by lower adverse prior year A&EP reserve development.

The following discusses the results of operations for our business segments.

Our property and casualty commercial insurance operations are managed and reported in three business segments: Specialty, Commercial and International, which we refer to collectively as Property & Casualty Operations. Specialty provides a broad array ofmanagement and professional financialliability and specialtyother coverages through property and casualty products and services through a network of independent agents, brokers and managing general underwriters. Commercial includes property and casualty coverages sold to small businesses and middle market entities and organizations primarily through an independent agency distribution system. Commercial also includes commercial insurance and risk management products sold to large corporations primarily through insurance brokers. International provides management and professional liability coverages as well as a broad range of other property and casualty insurance products and services abroad throughusing a network of brokers, independent agencies and managing general underwriters,underwriters. Commercial works with a network of brokers and independent agents to market a broad range of property and casualty insurance products and services to small, middle-market and large businesses. The International segment underwrites property and casualty coverages on a global basis through two insurance companies based in the U.K. and Luxembourg, a branch operation in Canada as well as the Lloyd’s marketplace.

Our operations outside of Property & Casualty Operations are managed and reported in two segments: Life & Group and Corporate & Other. Life & Group primarily includes the results of our long term care business that is in run-off. Corporate & Other primarily includes certain corporate expenses, including interest on corporate debt, and the results of certain property and casualty businesses in run-off, including CNA Re and A&EP. Intersegment eliminations are also included in this segment.

In evaluating the results of our Specialty, Commercial and International segments, we utilize the loss ratio, the expense ratio, the dividend ratio and the combined ratio. These ratios are calculated using GAAP financial results.

Changes in estimates of claim and claim adjustment expense reserves, and premium accruals, net of reinsurance, for prior years are defined as net prior year loss reserve development within this MD&A. These changes can be favorable or unfavorable. Net prior year loss reserve development does not include the effect of related acquisition expenses. Further information on our reserves is provided in Note E to the Consolidated Financial Statements included under Item 8.

Specialty provides management and professional liability and other coverages through property and casualty products and services using a network of brokers, independent agencies and managing general underwriters. Specialty includes the following business groups:

The following table details the results of operations for Specialty.

Gross written premiums, excluding third party captives, for Specialty increased $181 million in 2019 as compared with 2018 driven by strong retention and rate. Net written premiums for Specialty increased $104 million in 2017 were consistent2019 as compared with 2016. New business, renewal premium change and retention also remained at consistent levels.2018. The decreaseincrease in net earned premiums was consistent with the trend in net written premiums.

Core income decreased $40increased $42 million in 20172019 as compared with 2016,2018 primarily due to higher net investment income driven by limited partnership and common stock returns partially offset by lower favorable net prior year loss reserve development and higher net catastrophe losses partially offset by improved non-catastrophe current accident year underwriting results and higher net investment income.development.

The combined ratio of 90.2% increased 3.02.0 points in 20172019 as compared with 2016.2018. The loss ratio increased 3.01.6 points primarily due todriven by lower favorable net prior year loss reserve development and higher net catastrophe losses.development. Net catastrophe losses were $49$15 million, or 1.80.5 points of the loss ratio, for 2017,2019, as compared to $18with $26 million, or 0.6 points1.0 point of the loss ratio, for 2016. The loss ratio excluding catastrophes and development improved 1.3 points.2018. The expense ratio increased 0.4 points in 2017 was consistent2019 as compared with the same period in 2016.2018 driven by higher employee costs.

Favorable net prior year loss reserve development of $216$92 million and $305$150 million was recorded in 20172019 and 2016.2018. Further information on net prior year loss reserve development is in Note E to the Consolidated Financial Statements included under Item 8.

The following table summarizes the gross and net carried reserves for Specialty.

The following table details the results of operations for Commercial.

Gross written premiums for Commercial increased $343 million in 2019 as compared with 2018 driven by higher new business and rate. Net written premiums for Commercial increased $41$255 million in 20172019 as compared with 2016 driven by higher new business within Middle Markets, strong retention and positive renewal premium change. This was partially offset by an unfavorable premium rate adjustment within Small Business that is more fully discussed in Note F to the Consolidated Financial Statements under Item 8.2018. The increase in net earned premium was consistent with the trend in net written premiums.

Core income increased $30$132 million in 20172019 as compared with 2016,2018, primarily due to higher net investment income driven by limited partnership and common stock returns.

The combined ratio of 100.8% improved 0.3 points in 2019 as compared with 2018. The loss ratio was consistent with the favorablesame period over period effect ofin 2018. Less favorable net prior year loss reserve development and improved non-catastrophe current accident year underwriting results partiallyunfavorable retrospective premium development were largely offset by higher net catastrophe losses.

Favorable net prior year loss reserve development of $59$2 million and $25 million was recorded in 2017 as compared with unfavorable net prior year development of $53 million in 2016.2019 and 2018. Further information on net prior year loss reserve development is in Note E to the Consolidated Financial Statements included under Item 8.

The following table summarizes the gross and net carried reserves for Commercial.

The International providessegment underwrites property and casualty and specialty coverages on a global basis through its operationstwo insurance companies based in Canada, the United Kingdom, Continental EuropeU.K. and Singapore,Luxembourg, a branch operation in Canada as well as through its presence atHardy, our Lloyd’s of London.

The following table details the results of operations for International.

The following table summarizes the gross and net carried reserves for International.

The Life & Group segment primarily includes the results of our long term care business that is in run-off. Long term care policies were sold on both an individual and group basis. New enrollees in existing groups were accepted through February 1, 2016.

The following table summarizes the results of operations for Life & Group.

Core income increased $30results decreased $152 million in 20172019 as compared with 2016. This increase2018. The decrease was driven by favorable morbiditya $170 million charge related to recognition of an active life reserve premium deficiency partially offset by unfavorable persistencya $44 million reduction in the long term care business. Additionally, the release of long term care claim reserves resulting from the annual claimsclaim experience study in the third quarter of 2019. The favorable claim reserve development was higherprimarily due to lower claim severity than anticipated in 2017 as compared with 2016.

Corporate & Other primarily includes certain corporate expenses, including interest on corporate debt and the results of certain property and casualty business in run-off, including CNA Re and A&EP.

The following table summarizes the results of operations for the Corporate & Other segment, including intersegment eliminations.

The following table summarizes the gross and net carried reserves for Corporate & Other.

The significant components of Net investment income are presented in the following table. Fixed income securities, as presented, include both fixed maturity securities and equity securities, which substantially consist ofnon-redeemable preferred stock.

The components of Net realized investment resultsgains (losses) are presented in the following table.

Further information on our realized gains and losses, including our OTTI losses and derivative gains (losses), as well as our impairment decision process, is set forth in Notes A and B to the Consolidated Financial Statements included under Item 8.