Updates

** Shares of cryptocurrency exchange Coinbase Global COIN.O fall 1.8% to $258.67 in premarket

** Co says it expects to incur between $180 million and $400 million in costs related to a cyber attack

** COIN says cyber criminals had stolen account data for a "small subset" of its customers

** However, COIN says no passwords, private keys, or funds were exposed and Coinbase Prime accounts are untouched

** The company will not pay the $20 million ransom demand it received and says it will reimburse the customers who were tricked into sending funds to the attackers

** COIN says it has set up a $20 million reward for information on the attackers

** Earlier in the week, the company became the first digital asset player to be included in the benchmark S&P 500 index .SPX

** As of last close, COIN has gained nearly 6% YTD

(Reporting by Pritam Biswas in Bengaluru)

((Pritam.Biswas@thomsonreuters.com))