The increase for the years ended December 31, 2019 and 2018 reflects the acquisition of TWG on May 31, 2018. The decrease for the year ended December 31, 2017 was primarily due to a change in program structure impacting the accounting for revenues on a net instead of gross basis for a large client in Connected Living. The change in program structure had no impact on net income. The decrease for the year ended December 31, 2016 primarily relates to the Assurant Health wind-down and the sale of our Assurant Employee Benefits segment.
The year ended December 31, 2015 included higher loss experience and adverse claim development on 2015 individual major medical policies associated with Assurant Health.
The year ended December 31, 2017 included a $177.0 million one-time benefit from the reduction of net deferred tax liabilities following the enactment of the TCJA. The reduction of net deferred tax liabilities was recorded at the reportable segment level using our best estimate of deferred tax balances as of the December 22, 2017 enactment date.
Policy liabilities include future policy benefits and expenses, unearned premiums and claims and benefits payable.
Total book value per basic common share equals total Assurant, Inc. stockholders’ equity divided by the basic common shares outstanding. At December 31, 2019, 2018, 2017, 2016 and 2015 there were 60,693,295, 62,770,031, 53,078,396, 56,660,642, and 66,606,258 common shares, respectively, outstanding.
We have undertaken several acquisitions and dispositions, which are reflected in our results. On May 31, 2018, we acquired TWG Holdings Limited and its subsidiaries (as subsequently reorganized, “TWG”) for total consideration of $2.47 billion. On August 1, 2018, we sold our Mortgage Solutions business to Xome, an indirect wholly owned subsidiary of WMIH Corp. On December 3, 2018, we sold Time Insurance Company, a subsidiary of the runoff Assurant Health business, to Haven Holdings, Inc.
TWG. The increase was partially offset by a $163.9 million after-tax loss related to a change in the fair value of Iké following the Company’s decision to sell the business.
Global Lifestyle net income increased $111.6 million, or 37%, to $409.3 million for Twelve Months 2019 from $297.7 million for Twelve Months 2018, primarily due to strong organic growth in mobile and full-year contributions from TWG, partially offset by continued declines in Global Financial Services and Other. TWG contributed approximately $130 million of full year net income to Global Lifestyle in 2019 compared to $74.7 million of income, excluding the $9.3 million after-tax benefit for client recoverables, for seven months in 2018.
Global Preneed net income decreased $5.5 million, or 10%, to $52.2 million for Twelve Months 2019 from $57.7 million for Twelve Months 2018, primarily due to an out of period adjustment of $9.9 million related to a net over-capitalization of deferred acquisition costs occurring over a ten-year period. Excluding this adjustment, segment net income increased primarily due to overall growth in the business and lower mortality.
Our results depend on, among other things, the appropriateness of our product pricing, underwriting, the accuracy of our reserving methodology for future policyholder benefits and claims, the frequency and severity of reportable and non-reportable catastrophes, returns on and values of invested assets and our ability to manage our expenses and achieve expense savings. Our results will also depend on our ability to profitably grow all of our businesses, in particular our Connected Living, Multifamily Housing and Global Automotive businesses, and manage the pace of declines in placement rates in our Lender-placed Insurance business and the North American credit insurance business in Global Financial Services and Other. Factors affecting these items, including, but not limited to, conditions in financial markets, the global economy and the markets in which we operate, fluctuations in exchange rates and inflation, may have a material adverse effect on our results of operations or financial condition. For more information on these and other factors that could affect our results, see “Item 1A - Risk Factors.”
Our results may also be impacted by our ability to continue to grow in the markets in which we operate, including in our Connected Living, Multifamily Housing and Global Automotive businesses, and to manage our Lender-placed Insurance business, including the expected reduction in loans tracked from a financially insolvent client. Our mobile business is subject to volatility in mobile device trade-in volumes based on the actual and anticipated timing of the release of new devices and carrier promotional programs, as well as to changes in consumer preferences. Our Lender-placed Insurance revenues will also be impacted by changes in the housing market. In addition, across many of our businesses, we must respond to the threat of disruption. See “Item 1A - Risk Factors - Business and Competitive Risks - Significant competitive pressures, changes in customer preferences and disruption could adversely affect our results of operations.”
The fair market value of the fixed maturity securities in our investment portfolio and the investment income from these securities fluctuate depending on general economic and market conditions. The fair market value generally increases or decreases in an inverse relationship with fluctuations in interest rates, while net investment income realized by us from future investments in fixed maturity securities will generally increase or decrease with interest rates. We also have investments that are subject to pre-payment risk, such as mortgage-backed and asset-backed securities. Interest rate fluctuations may cause actual net investment income and/or cash flows from such investments to differ from estimates made at the time of investment. In periods of declining interest rates, mortgage prepayments generally increase and mortgage-backed securities, commercial mortgage obligations and bonds are more likely to be prepaid or redeemed as borrowers seek to borrow at lower interest rates. Therefore, in these circumstances we may be required to reinvest those funds in lower-interest earning investments.
If the actual level of loss frequency and severity are higher or lower than expected, the ultimate reserves required will be different than management’s estimate. The effect of higher and lower levels of loss frequency and severity on our ultimate costs for claims occurring in 2019 would be as follows:
Represents the sum of the case reserves and incurred but not reported reserves as of December 31, 2019 for Global Lifestyle and Global Housing.
We have exposure to asbestos, environmental and other general liability claims arising from our participation in various reinsurance pools from 1971 through 1985. This exposure arose from a contract that we discontinued writing many years ago. We carried case reserves for these liabilities, as recommended by the various pool managers, and IBNR reserves totaling $24.3 million (before reinsurance) and $20.7 million (net of reinsurance) at December 31, 2019. Estimation of these liabilities is subject to greater than normal variation and uncertainty due to the general lack of sufficiently detailed data, reporting delays and absence of a generally accepted actuarial methodology for determining the exposures. There are significant unresolved industry legal issues, including such items as whether coverage exists and what constitutes an occurrence. In addition, the determination of ultimate damages and the final allocation of losses to financially responsible parties are highly uncertain. Based on information currently available, and after consideration of the reserves reflected in the Consolidated Financial Statements, we do not believe or expect that changes in reserve estimates for these claims are likely to be material.
Reinsurance recoverables were $9.59 billion and $9.17 billion as of December 31, 2019 and 2018, respectively, which include amounts we are owed by reinsurers for claims paid as well as those included in reserve estimates that are subject to the reinsurance. Reinsurance premiums paid are amortized as reductions to premium over the terms of the underlying reinsured policies. Amounts recoverable from reinsurers are estimated in a manner consistent with claim and claim adjustment expense reserves or future policy benefits reserves. An estimated allowance for doubtful accounts is recorded on the basis of periodic evaluations of balances due from reinsurers (net of collateral), reinsurer solvency, historical disputes of reinsurance liabilities, management’s experience and current economic conditions. The ceding of insurance does not discharge our primary liability to our insureds.
We utilize reinsurance for loss protection and capital management, business dispositions and, in Global Lifestyle and Global Housing, client risk and profit sharing. See also “Item 1A - Risk Factors - Reinsurance may not be adequate or available to protect us against losses, and we are subject to the credit risk of reinsurers” and “