Remember the stay-at-home stocks? How the trendy have fallen.

Why it matters: The saga of the stay-at-home stocks is a useful reminder that hot new technology stocks can fall out of favor fast.

Driving the news: Two of the companies whose businesses seemed custom made for the COVID era — Zoom Video and Peloton — are making a splash this week.

• Ubiquitous video meeting software provider Zoom is down roughly 16% this week after it reported piddling sales growth and cut its forecasts for the year.
• Home exercise company Peloton was up 20% on Wednesday after it announced it would try to stem flagging sales by hawking products on Amazon. But it's down nearly that much today, after another ugly earnings report.

The big picture: While such moves are fairly large for any given week, they obscure the big story of these companies — a familiar one on Wall Street.

• It's called boom-and-bust.

Flashback: During peak COVID, a number of companies that were optimized for the WFH era posted remarkable gains, as customers flocked to their services.

• In 2020 alone, shares of both Peloton and Zoom were up an astounding 400%.
• Shopify, which helps brick-and-mortar retailers set up online stores, rose nearly 200%.
• Chegg, which offered digital textbook rentals, roughly doubled.

Today: Almost all those gains have vaporized.

Yes, but: Not all the companies that surged during COVID have collapsed.

• With many workplaces going to a hybrid home/office model, the need for online security continued to grow.
• Online security firms CrowdStrike and Zscaler rose more than 300% in 2020, and they've both held on to most of those gains.

Editor's note: This story has been updated to reflect Peloton's earnings report and stock price reaction.