 Shares of Weibo Corp. WB, -2.64 rose 1.1 in premarket trading Thursday, after the China-based social media company announced a 500 million American depositary share ADS repurchase program. The program, which will expire on March 31, 2023, represents 8.3 of Weibos market capitalization of 6.04 billion as of Wednesdays stock closing price of 24.68. 