What happened

Shares of freelancing website Upwork (UPWK 3.05%) and remote-communication company Slack Technologies (WORK) -- two of the best-known work-from-home stocks, and thus well-positioned to benefit from an economy where workers are being told not to come into the office but keep their "social distance" instead -- both closed lower today. So too did e-learning stock 2U (TWOU -3.84%).

By the time the closing bell struck, Slack shares were 9.5% lower, Upwork was down 17.8%, and 2U did worst of all -- down a staggering 28.4%.

Three colorful arrows all pointing down

Image source: Getty Images.

So what

Was there a specific reason for these stocks to be falling today?

Not really, no. No analysts downgraded any of the three. None of them reported poor earnings -- nor warned of poor earnings to come. As best I can tell, all three of these stocks declined just because "everything is going down."

Now what

And yet, if you look a little harder, there may be a reason for these stocks declining -- even in an economy that by all appearances is getting more and more conducive to their business models.

On the one hand, yes, fears of coronavirus are pushing more people to work, and learn, from home. Given enough time, this is a trend that could do very nice things for revenue at all three of these companies. But then again, growing revenue was never their problem, was it?

Over the past year, Upwork's sales were up 19% and Slack was no slacker either, growing sales 57%. 2U, too, grew its sales at a sprightly 40% over the past year. Despite this fact, to date, none of the three companies is earning any profit. None of them is generating any positive free cash flow, either.

Now, maybe a significant uptick in revenue from an increasingly "do stuff from home" economy will be the change that finally pushes these companies over the threshold to achieve critical mass, that finally turns them profitable. But they'll still need to survive, and remain solvent, long enough to reap the gains.

Today's stock-market action suggests investors still aren't 100% convinced that they'll make it.