(Bloomberg) -- Xiaomi Corp. suspended trading of its Hong Kong shares on Wednesday, after failing to disclose the city’s biggest-ever top-up placement in time for the market open.China’s No. 2 smartphone maker plans to submit a filing about the share sale so that trading can resume in the afternoon session, a person familiar with the matter said, asking not to be identified discussing private information. Xiaomi didn’t respond to requests for comment.The trading halt was first announced without explanation around 9 a.m. local time, just after the start of Hong Kong’s premarket auction. Xiaomi explained in another exchange filing more than two hours later that an official disclosure of the sale was still pending.The company’s failure to announce the stock sale more quickly came as a surprise to some market participants. The episode comes about a month after Hong Kong was rattled by an abrupt decision by Chinese regulators to yank Ant Group Co.’s planned initial public offering, which would have been the largest ever.“It’s definitely unusual because other companies which had share placements usually file the official announcements soon after pricing,” said Castor Pang, head of research at Core Pacific-Yamaichi International Hong Kong. “It’s hard to know what’s going on.”Xiaomi sold 1 billion shares in a top-up placement at HK$23.70 each, the bottom of a range, to raise $3.1 billion, according to deal terms obtained by Bloomberg News. That represents a 9.4% discount to its last closing price of HK$26.15.Wednesday’s premarket auction showed the stock trading as low as HK$24.50, implying a drop of 6.1%. Hong Kong’s stock exchange requires a company to apply for a trading halt if certain inside information has been made public before an official disclosure.Xiaomi also fetched $900 million through the sale of a seven-year, zero-coupon convertible bond, the terms showed. The proceeds will add to a war chest aimed at helping the company grab market share from competitors such as Huawei Technologies Co.Xiaomi shares have rallied 143% this year, though they slipped from a high last month after the company said its internet services revenue had grown at its slowest pace in three years in the quarter ended September. Xiaomi grabbed market share from Huawei when American sanctions deepened particularly in overseas markets from Europe to India.Credit Suisse Group AG, Goldman Sachs Group Inc, JPMorgan Chase & Co. and Morgan Stanley arranged Xiaomi’s offering.(Adds Xiaomi’s second exchange filing in third paragraph)For more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.©2020 Bloomberg L.P.