Sogou Inc. expects to hold a U.S. initial public offering (IPO) at a valuation of as much as $5 billion as it raises cash to close the gap with leader Baidu Inc. in the mobile market. Sogou plans to sell about 10% of its shares in an IPO that will probably be held this year, Chief Executive Officer, Wang Xiaochuan said. The company, which is backed by Tencent Holdings Ltd. and Sohu.com Inc., hasn’t formally hired banks to run the listing.