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Insurers' investments in real estate, private equity and other high-yielding assets rose 39% from 2015 to 2020. These so-called illiquid assets made up 35% of insurers' $4.04 trillion in investments as of Dec. 31, 2020, up from 32% in 2015. Higher yields have helped slow an industrywide decline in investment income since the financial crisis. A drawback is that the assets can be harder to sell than publicly traded bonds. MetLife said its U.S. insurance operations increased investments in the categories detailed by Moody's to 44.6% of total cash and invested assets in 2020, up from 38.1% in 2015. Life insurers have leeway to go with longer-term investments because most policies can't be cashed out on demand by consumers. MetLife, the nation's largest publicly traded life insurer, has a long history with a wide array of assets, including private agriculture loans. MetLife's private-equity investments returned $1.5 billion, or 12.6%, in the third quarter. Adjusted earnings for its U.S. group-benefits business dropped 72% to $111 million. Private equity funds represent just under 3% of MetLife's total cash and invested assets. Outsize results at publicly traded life insurers will make for tough comparisons in 2022.