That is because Rocket's underwriting banks helped prop up the German e-commerce and investment group's share price by narrowing the number of shares available for a so-called greenshoe over-allotment option.

Rocket's listing got off to a shaky start on Oct. 1, with shares down 14 percent within minutes of their stock market debut, forcing the underwriting banks to act.

Rocket had been touted as the largest IPO in Germany since Tognum in 2007, and the listing had even been brought forward by a week, citing "exceptional investor demand across all points of the price range" for its shares.

Regulatory filings to the Frankfurt Stock Exchange late on Friday, however, reveal that proceeds from Rocket's IPO did not reach 1.6 billion euros, leaving Telefonica Deutschland, which raised 1.45 billion euros two years ago, as the next biggest IPO in Germany in recent times.

Berenberg investment bank said it had carried out so-called stabilisation measures between Oct. 2 and Oct. 31 to prop up the company's shares, which had fallen in value by 25 percent from the 42.50 euros listing price.

The intervention was successful, with the Rocket Internet share price back up 42.50 euros on Friday, but it narrowed the over-allotment option for new shares and thereby lowered the IPO proceeds available for Rocket, the filings show.

(Reporting by Alexander Huebner, writing by Edward Taylor; Editing by Toby Chopra)