>>Shares up as much as 18.5 percent
"It'll be interesting over the next two or three years to see if InterXion makes a bigger play in the United States," said Todd Weller, Internet infrastructure analyst at Stifel Nicolaus & Co.
"They will have to prove they can compete," he said.
In the U.S. market, InterXion is facing competition from heavyweight incumbents such as Equinix Inc (EQIX.O), which last spring bought out Switch & Data, which had served as InterXion's access to the U.S. market through a business partnership.
Late last year, InterXion entered into another transatlantic agreement, partnering with privately held data center host Telx.
"We can read into these partnerships that it's a really important market for InterXion," Weller said, suggesting the European firm could expand by either building data centers in the United States or acquiring established U.S. peers.
InterXion's U.S. listing comes four months after people familiar with the matter said InterXion-owner Baker Capital had hired Morgan Stanley (MS.N) to explore a sale of the company.
However, some of the people said at the time that Baker's high price expectations -- equivalent to more than 10 times earnings before interest, tax, depreciation and amortization -- could deter bidders.
...Its top-of-range pricing on Thursday helped lift shares of its UK competitor, data center operator Telecity Group Plc (TCY.L), which rose as much as 6 percent to a six-week high on Friday.