Sites like Poshmark, eBay, and thredUp are getting slammed by the coronavirus crisis

This article is part of a FortuneSpecial Report: Business in the Coronavirus Economy—a look at the impact of the pandemic on more than 50 industries.

The fast growth of re-commerce—the online marketplaces for secondhand goods and one of retail’s hottest areas—came to a screeching halt on March 11. That was the day the World Health Organization declared that COVID-19 had become a pandemic.

For many Americans, it was the moment that an outbreak that had started in China and previously seemed remote really hit home. It instantly cooled any enthusiasm for shopping for anything other than bare necessities. Toilet paper suddenly became more desirable than that vintage Barneys New York cashmere sweater being resold for a song.

“When it really started to sink in for people, there was a huge shock to the system, and there was a real pullback in spending,” James Reinhart, cofounder and chief executive of ThredUp, tells Fortune.

Initially, the concerns were very practical too: Shell-shocked buyers wondered whether it was even safe to order things and receive packages, fretting whether the virus could still be on the items. Sellers wondered the same. (The World Health Organization and U.S. government agencies have said handling packages is safe.)

“There was a bit of confusion across the community of whether we should buy on Poshmark, or be selling on Poshmark,” says Poshmark CEO Manish Chandra.

Both Poshmark and ThredUp are privately held and wouldn’t quantify the drop in business in the past two weeks, but it is clear re-commerce, just like the rest of nonessential retail right now, is taking a big hit.

The RealReal, which is publicly traded and sells secondhand high-luxury products, pulled its 2020 financial forecasts last week because of coronavirus-related uncertainty. It has also had to close an e-commerce center in California and cancel appointments at its consignment stores. Luxury, even at lower prices, is typically the hardest hit part of retail during a crisis, especially when a big stock market swoon hits people’s perception of their own wealth. French luxe conglomerate said on Friday first-quarter sales could fall as much as 20% because of the virus crisis.

Yet slowly but surely, the re-commerce market is reawakening, as panic recedes and tens of millions of Americans find themselves stuck at home in front of computers.

“As people have digested the news, what we’ve seen is the new normal—not as good as it was before, but we expect to see business rebound,” says Reinhart.

Chandra, who said orders last week rose 20% over the week before, noted that Poshmark has seen a surge in items listed for sale. He ascribes some of that to the fact that many Americans, facing furloughs or job losses, are looking for a new source of income. (On Thursday, the Department of Labor said a record 3.3 million had filed for unemployment benefits.)

That has created another problem for re-commerce: Supply and demand are out of sync, pressuring prices on the main re-commerce sites, to the frustration of many sellers. Still, the companies say, balance is beginning to return.

“What I can’t tell you is whether that will take a few weeks or a few months. We’re over the panic of nobody is shopping at all,” says Reinhart, predicting re-commerce’s long-term prospects hold.

And that trajectory has made re-commerce one of the most promising areas in the beleaguered retail industry. A 2019 report by research firm GlobalData estimated sales of secondhand items excluding Goodwill and thrift shops in the U.S. would rise from $7 billion last year to $23 billion in 2023, with demand stoked by factors such as concerns for the environment and interest in vintage products.

But first the industry has to get past the current crisis. While the sector can’t predict or influence how quickly the coronavirus will be contained, the big re-commerce players are making some changes for the sellers on whom they rely to have a functioning marketplace. EBay for one says it is giving sellers more time to pay fees under some circumstances, and more time to ship items. The RealReal is helping sellers facilitate virtual appointments.

On the marketing side, there are also adjustments to everyone’s new reality. Poshmark had planned to hold so-called Posh N Coffee events, gatherings that bring together sellers (called “Poshers” by the company) to share tips and network, at many Starbucks stores across the country this weekend. Instead, 400 get-togethers will be held virtually via Zoom. The point, Chandra says, is to keep its marketplace participants in contact with each other through the current turmoil to ease the return to normal—whenever that might happen.

Apparel pullback

Poshmark, ThredUp, and the RealReal are all heavily focused on apparel, an industry that has seen sales plummet as shoppers focus on essentials. Some reports have suggested an 80% drop in clothing sales in some markets this month. (The impact may be less severe on sites that host a wider variety of products; an eBay spokesperson told Fortune that items for home-improvement projects and entertainment like video games were up, echoing comments by retailers like Best Buy and Lowe’s that sell such products new.)

In theory, the fact that big apparel chains like Gap Inc. and department stores like Kohl’s and Macy’s are enduring lengthy store closings should offer re-commerce a market share opportunity. But it’s not that simple.

Those chains and clothing retailers will eventually cut prices on unsold merchandise, slamming the whole apparel market.

“There’s likely to be significant discounting of apparel. Apparel retailers are likely to be overinventoried in the near term,” says Thomas O’Connor, a senior director and analyst at Gartner.

Much of that inventory is likely to end up at “off-price” stores like T.J. Maxx, which sells a lot of merchandise returned to vendors like Calvin Klein or Under Armour by department stores, or at discounters associated with the large chains, such as Nordstrom Rack. Those stores offer not only low prices but also some of the treasure hunt aspect shoppers find appealing about re-commerce.

What’s more, there is likely to be pressure on the resale sites from people’s inability to go to restaurants, the theater, bars—or even the office—for an extended period while countless major cities are under at least partial lockdowns. “Consumers are not going out nearly as much, therefore don’t need clothes to go out as much,” he said.

Yet O’Connor and other analysts see re-commerce’s ultimate ascent as incontrovertible. The only question is how long the current disruption lasts.

“It’s not going to go away, of course,” he says, of the industry. “But what’s the timeline for re-commerce to recover and reaccelerate?”