The components of net income are set forth in the following table:
Net investment income was $74.6 million, $73.2 million, and $72.2 million for the years ended December 31, 2017, 2016, and 2015, respectively. The average pre-tax book yield on our invested assets was 3.1%, 3.1%, and 3.2% at December 31, 2017, 2016, and 2015, respectively. The average tax-equivalent yield on our invested assets (which adjusts the book yield of our investments in tax-advantaged securities to an equivalent pre-tax book yield) was 3.5%, 3.6%, and 3.8% as of the same dates, respectively.
Excluding the impact from the LPT Agreement, losses and LAE would have been $428.8 million, $434.5 million, and $449.8 million, or 59.8%, 62.5%, and 65.2% of net premiums earned, for the years ended December 31, 2017, 2016, and 2015, respectively.
Total cash and investments held by our operating subsidiaries was $2,677.2 million at December 31, 2017, consisting of $34.7 million of cash and cash equivalents, $0.3 million of short-term investments, $2,431.9 million of fixed maturity securities, and $210.3 million of equity securities. Sources of immediate and unencumbered liquidity at our operating subsidiaries as of December 31, 2017 consisted of $33.7 million of cash and cash equivalents, $205.6 million of publicly-traded equity securities
The table below shows our net cash flows. For additional information regarding our cash flows, see Item 8, Consolidated Statements of Cash Flows.
Net cash provided by operating activities in 2017 included net premiums received of $702.4 million, and investment income received of $90.0 million. These operating cash inflows were partially offset by net claims payments of $419.2 million, underwriting and other operating expenses paid of $123.6 million, and commissions paid of $84.6 million.
Net cash used in financing activities in 2017 was primarily related to stockholder dividend payments and the purchase of a note payable.
We retain an independent actuarial consulting firm (Consulting Actuary) to perform comprehensive studies of our loss reserves on a semi-annual basis. The role of the Consulting Actuary is to conduct sufficient analyses to produce a range of reasonable estimates, as well as a point estimate, of our loss reserves, and to present those results to our Internal Actuary and to management as supplemental data in selecting management's best estimate of ultimate losses.
In January 2017, the FASB issued ASU Number 2017-04, Intangibles-Goodwill and Other (Topic 350). This update simplifies the measurement of goodwill by eliminating the performance of Step 2 in the goodwill impairment testing. This update allows the testing to be performed by comparing the fair value of a reporting unit with its carrying amount and recognizing an impairment charge when the carrying amount exceeds fair value. Additionally, this update eliminates the requirements of any reporting unit with a zero or negative carrying value to perform Step 2, but requires disclosure of the amount of goodwill allocated to a reporting unit with zero or negative carrying amount of net assets. This update becomes effective for fiscal years beginning after December
The preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. As a result, actual results could differ from these estimates. The most significant areas that require management judgment are the estimate of unpaid losses and loss adjustment expenses (LAE), evaluation of reinsurance recoverables, recognition of premium revenue, recoverability of deferred income taxes, and valuation of investments.
Policy acquisition costs, those costs that relate directly to the successful acquisition of new or renewal insurance contracts, including underwriting, policy issuance and processing, medical and inspection, and sales force contract selling are deferred and amortized as the related premiums are earned. Amortization of deferred policy acquisition costs for the years ended December 31, 2017, 2016, and 2015, was $108.2 million, $104.5 million, and $103.9 million, respectively.
The gross carrying value, accumulated amortization, and net carrying value for the Company's intangible assets, by major class, as of December 31, were as follows: