Registered investment companies Private assets Hedge funds e. Benefit Payments 68 Pension Benefit Payments Medical and Life Insurance Benefits Year Ending December 31, Gross Benefit Payments Medicare D Subsidy Net Benefit Payments (In millions) 2021 $ 106.9  $ 3.5  $ 0.1  $ 3.4  2022 103.8  3.1  0.1  3.0  2023 100.6  2.8  0.1  2.7  2024 97.1  2.5  0.1  2.4  2025 93.4  2.2  0.1  2.1  Years 2026 - 2030 409.1  7.6  0.2  7.4  December 31, 2018 Unrealized Gains (Losses) Realized Gains Purchases, Sales, and Settlements, net  December 31, 2019 (In millions) Equity securities:  Domestic equity securities $ 4.9  $ (0.3) $ 0.3  $ (0.7) $ 4.2   International equity securities 0.1  (0.1) —  —  —  Corporate debt securities 21.5  (0.1) 0.1  6.1  27.6  Private assets 1.3  0.2  0.1  3.8  5.4  Total $ 27.8  $ (0.3) $ 0.5  $ 9.2  $ 37.2  December 31, 2019 Unrealized Gains (Losses) Realized Gains Purchases, Sales, and Settlements, net  December 31, 2020 (In millions) Equity securities:  Domestic equity securities $ 4.2  $ 1.9  $ —  $ —  $ 6.1  Corporate debt securities 27.6  5.4  —  (1.1) 31.9  Private assets 5.4  1.7  1.3  (5.3) 3.1  Total $ 37.2  $ 9.0  $ 1.3  $ (6.4) $ 41.1  Registered investment companies are invested in corporate bonds, senior secured loans, and other fixed income. Registered investment companies are transacted at NAV published daily and are classified as Level 1 investments. Private assets are primarily limited partnerships that mainly invest in U.S. and non-U.S. leveraged buyout, venture capital and special situation strategies. Generally, the individual investments within the partnerships or funds are valued at public market, private market, or appraised value. Private assets are valued by investment managers using unobservable inputs such as extrapolated data, proprietary data, or indicative quotes. The majority of the private assets are valued at NAV and included as a reconciling item to the fair value tables above. Private assets for which there is no NAV are classified as Level 3 investments. Valuations of certain assets were based on the NAV or market value three months prior to the year-end. The Company made adjustments amounting to a decrease of $6.2 million and $17.4 million for 2020 and 2019, respectively, to account for changes since the valuation date. Hedge funds primarily consist of multi-strategy hedge funds that invest across a range of equity and debt securities in a variety of industry sectors. Hedge funds are valued at NAV calculated by investment managers using unobservable inputs such as extrapolated data, proprietary data, or indicative quotes and are included as a reconciling item to the fair value tables above. Valuations of certain assets were based on the NAV or market value three months prior to the year-end. The Company made adjustments amounting to a decrease of $4.5 million for 2019 to account for changes since the valuation date. The following tables present the changes in the fair value of the Level 3 investments: The following table presents estimated future benefit payments: