Dark Web Hackers Say They Hold Keys to 10,000 Robinhood Accounts

The dark web is the underbelly of the internet, where cyber-criminals hunt for drugs, demand ransom and engage in trafficking.

It’s also where hackers can buy and sell email credentials to access customer accounts at Robinhood Markets, the online brokerage that has drawn millions of users this year, many of them young and trading stocks for the first time.

Access to more than 10,000 email login credentials allegedly tied to Robinhood accounts were available for sale this week, according to a Bloomberg review of dark web marketplaces. The number of Robinhood-related emails outnumber those for other brokerages by about...