Asian stocks were mixed on Wednesday ahead of a policy decision by the U.S. Federal Reserve.
The widely anticipated trading debut of SoftBank Corp, the mobile unit of Japanese conglomerate SoftBank Group, ended in disappointment. The company's shares closed 14.5 percent lower than its initial public offering price of 1,500 yen ($13.36). It was the most heavily-traded stock on the Tokyo Stock Exchange.
SoftBank Corp's 2.65 trillion yen ($23.6 billion) IPO is the largest ever in Japan and the second-largest in the world behind Alibaba's $25 billion IPO in 2014.
"I'm not 100 percent surprised that it's down this much. If they'd been able to hold above that 1,500-level (IPO price), it could have been a different story," said Andrew Jackson, head of Japanese equities at SooChow CSSD Capital Markets Asia.
"Once it dipped below it, a lot of these retail investors, first-time investors who don't really know much about the markets, are probably in a big hurry to get out," Jackson told CNBC's "Street Sign," noting that around 90 percent of those that subscribed to SoftBank Corp's IPO were retail investors.
In the broader Japanese market, the Nikkei 225 finished the day 0.6 percent to 20,987.92 and the Topix closed 0.41 percent down to 1,556.15.