Sina (SINA, news, chart) shares are down $3.76 to $40.18, but implied volatility in the options is easing following the company’s earnings release. Shares of the Chinese Internet portal fell after the company beat earnings estimates for the most recent quarter, but results showed an unexpected jump in sales and marketing costs. Players in the options market are leaning on the bullish side despite the stock’s slide. 7,100 SINA calls have traded, compared to 3,100 put options. While some of the volume reflects some post-earnings premium selling, the August 40 calls are among the most actives, with 1,200 contracts traded and 82 percent trading offerside. Implied volatility is falling back below 50 percent, down 25 percent on the day.