Alibaba Group Holding has pushed its highly anticipated IPO until after the September Labor Day holiday, a source with knowledge of the matter told Reuters, as the Chinese online retail company works through the complex process of launching what could the largest-ever U.S. tech debut. Alibaba, which had targeted an August float, now plans to begin its investor roadshow and price its shares in September, the source said on condition of anonymity because the IPO process was private. Though the IPO remains on track, the Chinese company wanted to avoid the weeks before Labor Day, when many on Wall Street take off on their summer vacations, the source added. Alibaba has already begun reaching out to the investment community. It has held at least two rounds of meetings with financial analysts in its hometown of Hangzhou in eastern China, according to a second person familiar with the meetings. The company is expected to garner a valuation of as much as $200 billion.