One of Jack Dorsey's babies is having a very bad day.
Shares of Square plunged more than 20 percent Friday, putting it on track for its biggest daily loss ever, after the mobile payment firm reported a bigger-than-expected first-quarter loss.
The firm, one of two companies run by Dorsey, posted an adjusted quarterly loss of 14 cents a share on $379 million in revenue Thursday. Analysts had expected Square to post a loss of 9 cents a share on $344 million in revenue, according to a consensus estimate from Thomson Reuters.
SQ in 2016
The loss raised further questions about Dorsey's ability to run both Square and Twitter simultaneously.
"It's really hard to drive innovative companies, even one at a time, because the team has to be able to make really bold bets and feel like the entire organization is behind them," Josh Elman, a partner at Greylock, told CNBC's "Squawk on the Street" on Friday.
Square went public Nov. 19 and Dorsey has been Twitter's permanent CEO (for a second time) since Oct. 5.
Twitter in past year
"I think [Dorsey] is an incredible product thinker, but I think it's hard to see both companies going through the cultural change as public companies and continue to force the innovation while his time is split," Greylock's Elman said.