The rush into the stocks coincided with frenzied trading for options—contracts that allow investors to bet on price moves in stocks or protect their portfolios.

Some individual investors have said that they are drawn to the thrill of options trading, happy to take on higher risks for the prospect of big payouts.

They have used the bets to turbocharge their positions, eager to ride the relentless momentum in stocks like GameStop and AMC.

Call options, which allow investors the right to purchase stocks at a set price in the future, have recorded particularly heavy trading.