Our portfolio of fixed maturity and equity security investments is subject to market volatility especially in periods of instability in the worldwide financial markets. Over time, net investment income could also be impacted by volatility and by the general level of interest rates, which impact reinvested cash flow from the portfolio and business operations. Depending upon market conditions, which are unpredictable and remain uncertain, considerable fluctuation could exist in the fair value of our investment portfolio and reported total investment income, which could have an adverse impact on our financial condition, results of operations, and cash flows. Significant volatility has been seen in the global financial markets since the outbreak of the COVID-19 pandemic. The extent of the impact on our invested assets cannot be estimated with a high degree of certainty at this time given the ongoing developments of this pandemic and the related impacts on the financial markets.
compared to targets and higher vacation accruals as employees took less vacation in 2020 as a result of the COVID-19 pandemic.
As of December 31, 2020, we have access to a $100 million bank revolving line of credit with a $25 million letter of credit sublimit that expires on October 30, 2023. As of December 31, 2020, a total of $99.1 million remains available under the facility due to $0.9 million outstanding letters of credit, which reduce the availability for letters of credit to $24.1 million. We had no borrowings outstanding on our line of credit as of December 31, 2020. Investments with a fair value of $124.9 million were pledged as collateral on the line at December 31, 2020. These securities have no trading restrictions and are reported as available-for-sale securities and cash and cash equivalents in the Statements of Financial Position. The bank requires compliance with certain covenants, which include leverage ratios and debt restrictions. We were in compliance with our bank covenants at December 31, 2020.
(2) Net purchases of treasury stock in 2018, 2019 and 2020 includes the repurchase of our Class A common stock in the open market that were subsequently distributed to satisfy stock based compensation awards. See Note 11, "Incentive and Deferred Compensation Plans".
duration of changes in consumer behavior and driving patterns and the resulting impact to the Exchange’s growth and financial condition remain uncertain.
We earn management fees from the Exchange under the subscriber’s agreement for services provided. Pursuant to the subscriber’s agreement, we may retain up to 25% of all direct and affiliated assumed premiums written by the Exchange. The management fee rate is set at least annually by our Board of Directors. The management fee revenue is calculated by multiplying the management fee rate by the direct and affiliated assumed premiums written by the Exchange and is allocated between the two performance obligations we have under the subscriber's agreement. The first performance obligation is to provide policy issuance and renewal services. The second performance obligation is acting as the attorney-in-fact with respect to the administrative services.
$ 2,401 2,542 $ 945 $ 2,593 2,542 $ 1,020 $ 2,359 2,542 $ 928
Nonredeemable preferred stock 0 151 0 2,836 0 0 (2,987) 0
(1) Includes interest earned on note receivable from EFL of $1.6 million in 2018. The note was repaid in full in 2018.
Net gains (losses) recognized during the period $ 5,056 $ 1,484 $ (819)
(1) The rate of compensation increase for the employee plan is age-graded. An equivalent single compensation increase rate of 3.21% in 2020 and 2019 and 3.32% in 2018 would produce similar results.
We made stock repurchases in 2020, 2019, and 2018 outside of our publicly announced share repurchase program related to stock-based awards. See Note 11, "Incentive and Deferred Compensation Plans" for additional information.
AOCI (loss), beginning of year $ 5,664 $ 1,189 $ 4,475 $ (9,169) $ (1,926) $ (7,243) $ 3,410 $ 716 $ 2,694
AOCI (loss), end of year $ 29,384 $ 6,171 $ 23,213 $ 5,664 $ 1,189 $ 4,475 $ (9,169) $ (1,926) $ (7,243)