The popular crypto exchange will not pay extortionists $20 million in ransom but will reimburse you for stolen assets.

US cryptocurrency exchange Coinbase has been targeted by hackers who stole customer data and demanded $20mn to prevent its public disclosure, the company said on Thursday. The group, which next Monday is set to become the first crypto exchange to join the S&P 500, said the cyber demands were made on Monday.

Coinbase said hackers had paid multiple contractors and employees working in support roles to collect information. It has fired those involved.

Shares of Coinbase took another leg lower Thursday afternoon on a report the SEC is investigating whether the crypto exchange has misstated its user numbers.

Attackers used the data to contact victims and trick them into sending money.

The company is the first of its kind to join the landmark index. Cryptocurrency skeptics and fans alike say that gives the virtual tender a stamp of legitimacy, but can’t agree if it’s warranted.

Shares of Coinbase rose sharply Tuesday on news that it would be included in the benchmark S&P 500 this month.

Coinbase Global's shares jumped nearly 15% on Tuesday after the cryptocurrency exchange became the first digital asset player to be included in the benchmark S&P 500 index .

The firm says hackers have obtained customer information by paying off employees.