The highly anticipated debut of Alibaba Group Holding, the Chinese e-commerce group, will come amid the busiest year for initial public offerings since the technology bubble burst in 2000.
Alibaba's IPO, which could come as soon as Sept. 19, could raise more than $21 billion and claim Facebook's title of biggest tech IPO. It will usher in a fall season when plenty of new names sell shares for the first time in the U.S. market.
Returns from IPOs so far this year have been mixed. Some analysts say large swaths of the market, especially biotechnology stocks, are frothy.
The percentage of IPOs coming from money-losing companies has jumped to a 14-year high, according to Jay Ritter, a professor of finance and leading scholar of IPOs at the University of Florida.
The mixed financial results could dim enthusiasm for some of the hot names coming later this year, including web hosting company GoDaddy, airline Virgin America, and possibly burger chain Shake Shack, which has been exploring an IPO.
Roughly one-third of the 188 stocks that debuted this year are selling below their IPO price. New stocks have risen an average of 19 percent over the first three months of trading, compared with 36 percent in 2013, and 23 percent in 2012, according to research firm Dealogic in New York.
"With the exception of mature companies like Alibaba, a lot of the companies that have all the hype around them tend to under-perform beyond the first day. They just get squeezed to valuations that are beyond what they can absorb," said Kathleen Smith, who manages Greenwich, Connecticut-based Renaissance Capital's IPO ETF.
MediWound, a biopharmaceutical company, serves as a cautionary tale. Its shares down 60 percent from the first closing price.