Sexual misconduct claims have toppled many powerful men in recent years, including the billionaire casino mogul Steve Wynn. But few companies have faced regulatory fines for how they handled the accusations.

On Tuesday, the Nevada Gaming Commission fined Wynn Resorts, the casino empire that Mr. Wynn founded and ran for years, $20 million for ignoring multiple complaints about his behavior.

The fine, which the commission approved unanimously, is the largest imposed against a gambling licensee in Nevada. The previous record was $5.5 million in 2014.

“It demonstrates a recognition that papering over sexual harassment and assault is a form of corporate corruption that is within the scope of regulators’ jurisdiction,” said Emily Martin, the vice president for education and workplace justice at the National Women’s Law Center. “It is an important reflection of the fact that, while harassment and assault harms victims and they need to be compensated, it also has broader harms.”