Caesars Entertainment, self-described as the largest U.S. casino chain with the most extensive loyalty program in the industry, says it paid a ransom to avoid the online leak of customer data stolen in a recent cyberattack.

Caesars’ 8-K also implies that a ransom demanded by the attackers was paid to prevent the leak of the stolen data online—a Wall Street Journal report says the hotel and casino entertainment company paid roughly $15 million, half of the attackers’ initial $30 million demand.