The Company may also incur significant additional capital expenditures as a result of unanticipated developments, regulatory changes and other events that impact the business.

Video streaming services and peer-to-peer file sharing applications use significantly more bandwidth than traditional Internet activity such as web browsing and email. As utilization rates and availability of these services continue to grow, our high-speed Internet customers may use much more bandwidth than in the past. If this occurs, we could be required to make significant capital expenditures to increase network capacity in order to avoid service disruptions or reduced capacity for customers.

The law relating to the liability of private network operators for information carried on, stored or disseminated through their networks is still unsettled. As such, we could be exposed to legal claims relating to content disseminated on our networks. Claims could challenge the accuracy of materials on our network or could involve matters such as defamation, invasion of privacy or copyright infringement. If we need to take costly measures to reduce our exposure to these risks or are required to defend ourselves against such claims, our financial results would be negatively affected.

Cyber attacks or other breaches of network or information technology security may cause equipment failures or disruptions to our operations. Our inability to operate our wireline networks as a result of such events, even for a limited period of time, may result in significant expenses and/or loss of market share to other communications providers.share. In addition, the potential liabilities associated with these events could exceed the insurance coverage we maintain. Cyber attacks, which include the use of malware, computer viruses and other means for disruption or unauthorized access, have increased in frequency, scope and potential harm in recent years. These risks may be heightened as we expand our managed services, data center services and cloud-based services. While, to date, we have not been subject to cyber attacks or other cyber incidents which, individually or in the aggregate, have been material to our operations or financial condition, the preventative actions we take to reduce the risk of cyber incidents and protect our information technology and networks may be insufficient to repel a major cyber attack in the future. Significant security failures could result in the unauthorized use or disabling of our network elements. The costs associated with a major cyber attack could include expensivematerial incentives offered to existing customers and business partners to retain their business, increased expenditures on cyber security measures, lost revenues from business interruption, litigation, fines from regulatory authorities and damage to our reputation. If we fail to prevent the theft of valuable information such as financial data, sensitive information about the Company and intellectual property, or if we fail to protect the privacy of customer and employee confidential data against breaches of network or information technology security, it wouldcould result in damage to our reputation, which could adversely impact customer and investor confidence. Any of these occurrences could result in a material adverse effect on our results of operations and financial condition.

Our business operations are subject to interruption by natural disasters, power outages, terrorist attacks, other hostile acts and events beyond our control. Such events could cause significant damage to our infrastructure, resulting in degradation or disruption of service to our customers. While we maintain insurance coverage for some of these events, theThe potential liabilities associated with these events could exceed the insurance coverage we maintain. Our system redundancy may be ineffective or inadequate and our disaster recovery planning may not be sufficient for all eventualities. These events could also damage the infrastructure of suppliers that provide us with the equipment and services we need to operate our business and provide products to our customers. A natural disaster or other event causing significant physical damage wouldcould cause us to experience substantial losses resulting in significant recovery time and expenditures to resume operations. In addition, these occurrences could result in lost revenues from business interruption as well as damage to our reputation.

The Company depends on third-party providers to supply products and services. For example, many of the Company's information technology and call center functions are performed by third-party providers, and network equipment is purchased from and maintained by vendors. The loss of, or problems with, one or more of these third-party providers may result in an adverse effect on our ability to provide products and services to our customers and on our results of operations and financial condition.

The efficient operation of the Company’s business depends on back-office information technology systems. The Company relies on back-office information technology systems to effectively manage customer billing, business data, communications, supply chain, order entry and fulfillment and other business processes. A failure of the Company’s information technology systems to perform as anticipated could disrupt the Company’s business and result in a failure to collect accounts receivable, transaction errors, processing inefficiencies, and the loss of sales and customers, causing the Company’s reputation and results of operations to suffer. In addition, information technology systems may be vulnerable to damage or interruption from circumstances beyond the Company’s control, including fire, natural disasters, systems failures, security breaches and viruses. Any such damage or interruption could have a material adverse effect on the Company’s business.

The Company is a party to collective bargaining agreements with its labor union,unions in both the Cincinnati and Hawaii operating territories, which represents approximately 30%35% of its employees. No assurance can be given that the Company will be able to successfully extend or renegotiate its collective bargaining agreements in the future. If the Company fails to extend or renegotiate its collective bargaining agreements, if disputes with its union arise, or if its unionized workers engage in a strike or a work stoppage, the Company could experience a significant disruption of operations or incur higher ongoing labor costs, either of which wouldcould have a material adverse effect on the business.

The Company’s success will continue to depend to a significant extent, on its senior management team and key sales associates.associates and the Company’s ability to retain such key management personnel and other key employees. Senior management has specific knowledge relating to the Company and the industry that would be difficult to replace. In particular, the success of the Company’s acquisition of Hawaiian Telcom will depend in part on the ability of the Company to retain key management and other key personnel of Hawaiian Telcom after the acquisition and to continue to attract such persons to the Company. The loss of key sales associates could hinder the Company’s ability to continue to benefit from long-standing relationships with customers. The Company cannot provide any assurance that it will be able to retain the current senior management team or key sales associates.associates nor any key management personnel or other key employees from Hawaiian Telcom. The loss of any of these individuals could adversely affect the Company’s business, financial condition, results of operations and cash flows.

As of December 31, 2015,2018, the Company and its subsidiaries had outstanding indebtedness of $1,245.6$1,929.8 million, on which it incurred $103.1$131.5 million of interest expense in 2015,2018, and had a total shareowners’ deficit of $298.2$75.0 million. In October 2017, the Company entered into a new Credit Agreement. The Credit Agreement provides for (i) a five year $200 million senior secured revolving credit facility including both a letter of credit subfacility of up to $30 million and a swingline loan subfacility of up to $25 million (the "Revolving Credit Facility") and (ii) a seven-year $600 million senior secured term loan facility (the "Tranche B Term Loan due 2024"). At December 31, 2015,2018, the Company and its subsidiaries had $90.3$9.1 million of borrowing availability under its Receivables Facility and had the ability to borrow up to an additional $175.0$182.0 million under the CorporateRevolving Credit Agreement's revolving credit facility,Facility, subject to compliance with certain conditions. In addition, the Company's ability to incur additional debt from time to time is subject to the restrictions contained in its credit facilities and other debt instruments.

The Company’s debt has important consequences, including the following:

The Company’s creditors and preferred stockholders have claims that are superior to claims of the holders of the Company's common stock. Accordingly, in the event of the Company’s dissolution, bankruptcy, liquidation, or reorganization, payment is first made on the claims of creditors of the Company and its subsidiaries, then preferred stockholders, and finally, if amounts are available, to holders of the Company's common stock.

The Company’s debt instruments impose, and the terms of any future debt may impose, operating and other restrictions on the Company. These restrictions affect, and in many respects limit or prohibit, among other things, the Company’s ability to:

In addition, the Company’s Corporate Credit Agreement and debt instruments include restrictive covenants that may materially limit the Company’s ability to prepay debt and redeem preferred stock. The agreements governing the Corporate Credit Agreement also require the Company to achieve and maintain compliance with specified financial ratios.

The restrictions contained in the terms of the Corporate Credit Agreement and its other debt instruments could:

As of December 31, 2015, the Company had no outstanding borrowings under the Corporate Credit Agreement's revolving credit facility, leaving $175.0 million in additional borrowing availability under this facility. The $175.0 million available under the Corporate Credit Agreement's revolving credit facility is funded by various financial institutions. If one or more of these banks is not able to fulfill its funding obligations, the Company’s financial condition would be adversely affected.

As of December 31, 2015,2018, the Company had $17.6$18.0 million of outstanding borrowings and $6.3under the Revolving Credit Facility, leaving $182.0 million in additional borrowing availability under this facility. The $200.0 million available under the Revolving Credit Facility is funded by various financial institutions. If one or more of lettersthese banks is not able to fulfill its funding obligations, the Company’s financial condition could be adversely affected.

The Company’s ability to generate cash is subject to general economic, financial, competitive, legislative, regulatory, and other factors, many of which are beyond its control. The Company cannot provide assurance that its business will generate sufficient cash flow from operations, that additional sources of debt financing will be available, or that future borrowings will be available under its CorporateRevolving Credit AgreementFacility Credit or Receivables Facility, in each case, in amounts sufficient to enable the Company to service its indebtedness or to fund other liquidity needs. If the Company cannot service its indebtedness, it will have to take actions such as reducing or delaying capital expenditures, strategic acquisitions, investments and alliances, or selling assets, including its investment in CyrusOne, restructuring or refinancing indebtedness, or seeking additional equity capital, which may adversely affect its shareholders, debt holders and customers. The Company may not be able to negotiate remedies on commercially reasonable terms, or at all. In addition, the terms of existing or future debt instruments may restrict the Company from adopting any of these alternatives. The Company’s inability to generate the necessary cash flows could result in its dissolution, bankruptcy, liquidation or reorganization.

The market price of the Company's common stock has been volatile and could be subject to wide fluctuations in response to, among other things, the risk factors described in this report and other factors beyond the Company's control, such as volatility in equity markets and fluctuations in the valuation of companies perceived by investors to be comparable to the Company.

Equity markets have experienced price and volume fluctuations that have affected the Company's stock price and the market prices of equity securities of many other companies. These broad market and industry fluctuations, as well as general economic, political, and market conditions, may negatively affect the market price of the Company's stock.

Companies that have experienced volatility in the market price of common shares have periodically been subject to securities class action litigation. The Company may be the target of this type of litigation in the future. Securities litigation could result in substantial costs and/or damages and divert management's attention from other business concerns.

The uncertain economic environment could have an adverse effect on the Company's business and financial liquidity. The Company's primary source of cash is customer collections. If economic conditions were to worsen, some customers may cancel services or have difficulty paying.paying their accounts receivable. These conditions would result in lower revenues and increases in the allowance for doubtful accounts, which would negatively affect the results of operations. Furthermore, the sales cycle would be further lengthened if business customers slow spending or delay decision-making on the Company's products and services, which would adversely affect revenues. If competitors lower prices as a result of economic conditions, the Company would also experience pricing pressure. If the economies of the U.S. and the world deteriorate, this could have a material adverse effect on the Company's business, financial condition, results of operations and cash flows.

As of December 31, 2015,2018, the Company had net deferred income taxestax assets of $182.9$244.2 million, which are primarily composed of deferred tax assets associated with U.S. federal net operating loss carryforwards of $90.5$124.4 million, state and state, local net operating loss carryforwards of $58.3 million, and foreign net operating loss carryforwards of $51.5$1.3 million. The Company has recorded a valuation allowancesallowance against deferred tax assets related to certain state, local and foreign net operating losses and other deferred tax assets due to the uncertainty of the Company’s ability to utilize the assets within the statutory expiration period. In addition the Company has recorded a valuation allowance against the portion of interest expense that is not currently deductible for domestic federal income tax due to the The Tax Cuts and Jobs Act of 2017 (the "Tax Act") effective December 31, 2017. The use of the Company’s deferred tax assets enables it to satisfy current and future tax liabilities without the use of the Company’s cash resources. If the Company is unable for any reason to generate sufficient taxable income to fully realize its deferred tax assets, or if the use of its net operating loss carryforwards is limited by Internal Revenue Code Section 382 or similar state statute,statutes, the Company’s net income, shareowners’ deficit and future cash flows would be adversely affected.

The Company sponsors three noncontributory defined benefit pension plans: oneplans for eligible management employees, one for non-management employees and one supplemental, nonqualified, unfunded plan for certain former executives. The Company also provides healthcare and group life insurance benefits for eligible retirees. The Company’s Consolidated Balance Sheets indirectly reflect the value of all plan assets and benefit obligations under these plans. The accounting for employee benefit plans is complex, as is the process of calculating the benefit obligations under the plans. Adverse changes in interest rates or market conditions, among other assumptions and factors, could cause a significant increase in the Company’s benefit obligations or a significant decrease of the asset values, without necessarily impacting the Company’s net income. In addition, the Company’s benefit obligations could increase significantly if it needs to unfavorably revise the assumptions used to calculate the obligations. These adverse changes could have a further significant negative impact on the Company’s shareowners’ deficit. In addition, with respect to the Company’s pension plans, the Company expects to make approximately $22 million of estimated aggregate cash contributions to its qualified pension plans for the years 2016 to 2019. Additionally, the Company’s postretirement costs are adversely affected by increases in medical and prescription drug costs. Further, if there are adverse changes to plan assets or if medical and prescription drug costs increase significantly, the Company could be required to contribute additional material amounts of cash to the plans, or couldto accelerate the timing of required payments.

The Company may be unaware of intellectual property rights of others that may cover some of its technology, products or services. Any litigation growing out of third-party patents or other intellectual property claims could be costly and time-consuming and would divert the Company’s management and key personnel from its business operations. The complexity of the technology involved and the uncertainty of intellectual property litigation increaseincreases these risks. Resolution of claims of intellectual property infringement might also require the Company to enter into costly license agreements. Likewise, the Company may not be able to obtain license agreements on acceptable terms. The Company also may be subject to significant damages or injunctions against the development and sale of certain of its products or services. Further, the Company often relies on licenses of third-party intellectual property for its businesses. The Company cannot ensure these licenses will be available in the future on favorable terms or at all.

The Company’s success significantly depends in significant part on the competitive advantage it gains from its proprietary technology and other valuable intellectual property assets. The Company relies on a combination of patents, copyrights, trademarks and trade secrets protections, confidentiality provisions and licensing arrangements to establish and protect its intellectual property rights. If the Company fails to successfully enforce its intellectual property rights, its competitive position could suffer, which could harm its operating results.

The Company may also be required to spend significant resources to monitor and police its intellectual property rights. The Company may not be able to detect third-party infringements and its competitive position may be harmed before the Company does so. In addition, competitors may design around the Company’s technology or develop competing technologies. Furthermore, some intellectual property rights are licensed to other companies, allowing them to compete with the Company using that intellectual property.

The industry that the Company operates in faces a substantial amountrisk of litigation, including, from time to time, patent infringement lawsuits, antitrust class actions, securities class actions, wage and hour class actions, personal injury claims and lawsuits relating to our advertising, sales, billing and collection processes. We may incur significant expenses in defending these lawsuits. In addition, we may be required to pay significant awards and settlements.