NEW YORK (AP) — It was one year ago that the terrifying free fall for the stock market suddenly ended, ushering in one of its greatest runs.

On March 23, 2020, the S&P 500 fell 2.9%. In all, the index dropped nearly 34% in about a month, wiping out three years' worth of gains for the market.

That turned out to be the bottom, even though the coronavirus pandemic worsened in the ensuing months and the economy sank deeper into recession. Massive amounts of support for the economy from the Federal Reserve and Congress limited how far stocks would fall. The market recovered all its losses by August...