Alibaba, which sells more than Amazon.com Inc and EBay Inc combined, could raise over $21 billion in its IPO. It is often described as technology’s hottest initial public offering since Facebook Inc’s 2012 debut, although initial pricing announced on Friday was less than many predicted. Retail investors generally get only 10-20 percent of shares in big IPOs, and several advisers told Reuters they had expected a scramble from clients. “People are on Facebook, they know it, but no one has ever heard of Alibaba,” said Mecca, who has $175 million in assets under management.