Robinhood took a $57 million hit after a glitch allowed its customers to short a surging meme stock

• Robinhood made a "processing error" that left its customers short on a meme stock last year.
• The error lost the trading app $57 million, the company's finance chief said on a Q4 earnings call.
• Robinhood stock rose Thursday after it said it will buy back shares seized from FTX founder Sam Bankman-Fried.

Robinhood ended up down $57 million in a single day after a glitch let its trading app customers temporarily short a meme stock, according to company executives.

Little-known Cosmos Health's share price tripled on December 16, when a 1-to-25 reverse stock split for the healthcare company went into effect.