Bitcoin whale makes ‘enormous’ losing bet, so now other traders have to foot the bill

• A trader on Hong Kong-based exchange OKEx made “an unusually large long position order" worth about $416 million and was unable to cover the loss as bitcoin prices slumped last week.
• Because the exchange's insurance fund couldn't cover it, other customers will have a portion of their earnings used to pay the bill.
• The event shines a light on risks of trading cryptocurrency, even on the world’s biggest exchanges.

A man talks on a mobile phone in a shop displaying a bitcoin sign in Hong Kong.

Philippe Lopez | AFP | Getty Images

An "enormous" losing bet on bitcoin last week left one futures trader unable to cover the loss and other traders on a Hong Kong-based exchange to foot the bill.

The gamble made on OKEx, one of the world's largest cryptocurrency exchanges, was worth about $416 million, according to a company statement and the price of bitcoin futures Friday.

Because of the sheer size of the order and bitcoin's price slump the exchange said it couldn't cover the loss. As a result, it implemented a clawback policy or what it called a "societal risk management mechanism." Users with a net profit will have a portion of their earnings taken back to cover the difference between the liquidated price and the settled price.

The trader, identified only as "ID 2051247," initiated what the exchange called "an unusually large long position order" of more than 4 million contracts on July 31. The exchange said it immediately contacted the client and requested "several times to partially close the positions to reduce the overall market risks."

"However, the client refused to cooperate, which lead to our decision of freezing the client's account to prevent further positions increasing," OKEx said on its website. "Shortly after this preemptive action, unfortunately, the BTC price tumbled, causing the liquidation of the account."

Although customers agreed to the clawback policy when they sign up for the exchange, the event threatens confidence in one of the world's biggest cryptocurrency exchanges, and highlights the risks of trading there.

"That exchange shouldn't have let someone put that size of a position," said Brian Kelly, CEO and founder of BKCM. "People could stop using that exchange, but even then, it doesn't have marketwide implications."

Kelly said that while $416 million was the size of the position, the real amount customers will have to pay out is closer to $15 million.

Bitcoin fell roughly 1 percent at midday Friday to $7,463, according to data from industry site CoinDesk. The cryptocurrency is down roughly 10 percent this week and has dropped roughly 50 percent this year.