Robinhood Outages Show Perils of Move Fast and Break Things

“Move fast and break things” is synonymous with Silicon Valley’s freewheeling tech culture. But one finance startup is learning the hard way that customers don’t like it when things actually break.

As the coronavirus set off violent swings in global stocks, Robinhood Financial Inc.’s trading platform kept failing. A series of major outages left millions of clients in the dark. Some pulled their accounts and went to competitors. Many vented frustrations online as Robinhood worked on fixes.

It wasn’t merely bad PR. Amid the volatility, the Menlo Park, California-based broker drew one of its credit lines.

The tumult is the ...