Tilman Fertitta has acquired a big ownership stake in Wynn Resorts Ltd., giving him an immediate foothold in the Las Vegas Strip’s casino industry as the billionaire sets out to build a towering resort on Las Vegas Boulevard.

Fertitta acquired 6.9 million shares in Las Vegas-based Wynn, comprising a 6.1 percent ownership stake, according to a filing Monday with the Securities and Exchange Commission.

According to the filing, the “date of event” was Oct. 19 — the same day the Clark County Commission approved Fertitta’s plans to develop a 43-story hotel-casino on the Strip.