Golden Nugget, the Las Vegas casino operator, announced a tender offer starting next Wednesday to buy up to 10 million of its 34.5 million outstanding shares at $13.25 each, or a maximum of $132.5 million. The company's shares closed Thursday at $11.875, up 12.5 cents on the New York Stock Exchange. Some observers interpreted the move as an anti-takeover defense. Officers and directors own about 20% of Golden Nugget's stock, which the buyback could raise to about 28%. The firm's stock jumped to $13.50 the day after New York financier Donald Trump disclosed July 9 that he had acquired 4.9% of Golden Nugget's shares, but the price has since dipped back below $12.