Sina (SINA +1.9%) adds to yesterday's Alibaba-fueled gains after receiving an upgrade to Buy from Jefferies; the firm is raising its PT to $75. Wedge Partners notes the Alibaba deal, which gives the Chinese e-commerce giant the potential to raise its stake to 30% from an initial 18% in time, values Sina at ~$54/share, a little below its current trading price. But many on the Street are betting the monetization opportunities the deal opens up for Weibo will justify a higher valuation. (yesterday: I, II)