Reasonable people can argue about whether the broader stock market is overheating. But in certain corners of the equity universe where tiny investors dominate, it’s hard to say everything is going normally.

Fact: shortly before 1 p.m. New York time Thursday, there were six penny stocks posting daily gains of at least 9,900%. Off-exchange venues where unlisted equities trade had seen about 38 billion shares change hands, up sevenfold from the average a year ago.

Ascribe it to what you want: a boom in retail trading triggered by injections of government cash, stay-at-home orders and commission-free brokerages, maybe even the buy-low approach on steroids. More than 1 trillion shares changed hands in December over lightly regulated quotation systems run by firms like OTC Markets.

In a note titled “This Is Ludicrous,” Bespoke Investment Group summed up the recent action. It cited 59 U.S.-listed stocks that are trading at prices that are more than 10 times sales and have more than doubled in the past three months. Stocks currently in that category have risen 760% since March and have a combined market capitalization of $320 billion, according to George Pearkes, global macro strategist at the firm.

“There are an awfully large number of stocks that have both exploded higher and trade at a ‘that can’t be real’ multiple,” Pearkes wrote. “There are almost always a few names in this bucket, but over the last few months this number has exploded up to 59 at the moment.”

Among larger companies, startling moves are becoming commonplace -- although at least there’s usually a kernel of news driving the swings.

GameStop Corp., a stock day traders have been obsessed with for months but one that’s rated “buy” by only one of eight analysts who cover it, has doubled over the past two days after activist investor and Chewy Inc. co-founder Ryan Cohen joined its board.