Weibo, the influential microblogging service owned by Sina, has reportedly raised just $285.6 million in its initial public offering. Weibo, which has about 143.8 million monthly active users and is known for its impact on public discourse in China, sold 16.8 million American Depositary Shares for $17 each. Those figures mean it underperformed Sina’s own expectations, which were to sell 20 million ADSs at between $17 and $19 per share.