Shares of Wynn Resorts Ltd. fell 0.8% in premarket trade Thursday, adding to the previous session’s 2.9% selloff, after Stephen Wynn, the founder and former chief executive, disclosed the sale of about one-third of his stake in the casino operator. Wynn, who stepped down as CEO last month following allegations of sexual misconduct, said in an SEC filing that he sold 4,104,199 common shares at $180 on Wednesday, for a value of $738.9 million. On Wednesday, the stock traded in an intraday range of $178.59 to $183.04 and closed at $178.92. The sale brings Wynn’s stake down to 8,026,708, or 7.8% of the shares outstanding, which would make him the third-largest shareholder, behind The Vanguard Group at 8.5% and his ex-wife Elaine Wynn at 9.3%, according to FactSet. In Thursday’s filing, Wynn said he intends to sell all or a portion of the stake controlled by him. At Wednesday’s closing price, Wynn’s remaining stake is worth about $1.44 billion. Wynn Resorts’s stock has rallied 6.7% over the past three months through Wednesday, while the S&P 500 has gained 1.1%.