Tim Culpan is a Bloomberg Opinion columnist covering technology. He previously covered technology for Bloomberg News. Read more opinion LISTEN TO ARTICLE 2:42 SHARE THIS ARTICLE Share Tweet Post Email

Photographer: Besjunior/Getty Images Photographer: Besjunior/Getty Images

Investors lucky enough to secure shares in a big IPO and not be constrained by a lockup would be advised to offload them immediately.

And if you’re eyeing the next blockbuster like Xiaomi Corp., don’t even bother.

I ran the numbers on more than 1,300 IPOs in the tech, media and telecoms (TMT) space over the past five years and found that while 81.3 percent rose on day one, just 49.2 percent continued to climb over the subsequent year.

It Gets Worse, Believe Me While most IPOs do well on debut, the majority go on to decline over the following six months and one year Source: Bloomberg, analysis Bloomberg Opinion

With lock-up periods for pre-IPO and cornerstone investors generally expiring after six months, it’s notable that between six months and one year post listing is the real danger zone, with only 40 percent of companies climbing in that timeframe.

Bad Bet Around 60 percent of shares decline between six months and one year after IPO, a timeline that coincides with the end of many lock-up periods Source: Bloomberg, analysis by Bloomberg Opinion

And the bigger the offering, the worse it gets.

Of the top 20 IPOs by sale size, just six rose from the end of the first day’s trading through to one year after debut. Eleven fell and three haven’t been trading for one whole year yet, so I didn’t count them.

Among the top 10 by offer size, only Auto Trader Group Plc climbed from debut close to the end of the first 12 months.

Foxconn Industrial Internet Co. is the second-largest TMT offering behind Alibaba Group Holding Ltd., raising $4.3 billion. It popped by the daily 44 percent limit last month, but has since dropped. iQiyi Inc., the sixth largest, fell 13.6 percent on its first day in March, tripled over the following 10 weeks and then slid to around 25 percent below its June 20 peak.

Big Losers The larger the offer size, the more likely a stock will drop after its first day of trading Source: Bloomberg, analysis Bloomberg Opinion

Shareholders of Adyen NV, a Dutch payments processor, seem to be holding on to the stock in the belief there’s still upside after its 90 percent jump on debut last month. Three weeks later, it’s maintained that valuation.

History, however, is not on Adyen’s side.

The negative correlation between size and returns is slightly more pronounced when using a metric called “market value upon listing,” by which Adyen ranks ninth.

Of the 10 biggest companies by value on listing, zero climbed between the end of day one through to the end of the first year. Not one. Nada. The “best” performer was Twitter Inc., which jumped 73 percent on its first day, only to slide 9 percent over the next year. Both Alibaba and Snap Inc. (up 44 percent on debut) dropped 30 percent in the subsequent period.

All (Not) Rise None of the world's biggest TMT IPOs climbed in the year after their initial first day pop Source: Bloomberg, analysis Bloomberg Opinion

Of course, companies that IPO aren’t destined to be share-market losers forever. The last five years have seen a bull run for the TMT sector; the MSCI World Information Technology Index is up 130 percent. But investors determined to buy into new tech firms for the long haul would be best to wait at least a year for the IPO hangover to pass.

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.