* Bain, Advent, Danish pension fund ATP agree to buy Nets
* Payment firm wants money to invest in new systems
* New owners expect to exit investment through IPO (Adds Bain, Advent quotes, background)
By Teis Jensen and Simon Johnson
COPENHAGEN/STOCKHOLM, March 24 A consortium led by two U.S. private equity firms agreed on Monday to buy payment services company Nets Holding from a group of Nordic banks for 17 billion Danish crowns ($3.14 billion).
Payment firms face a host of challenges from a shift in transactions from credit and debit cards to online and mobile payments, increased scrutiny from regulators and the need for huge IT investment to secure data from prying eyes.
After a strategic review last year, Nets decided it should no longer be owned by its customers and needed money to invest in new systems.
Private equity firms Advent International and Bain Capital, along with Danish pension fund ATP, have agreed to buy Nets.
They said they would continue to focus the payment firm on the Nordic market and would look at expanding within the region.
"We think that Nets has great opportunities both organically and inorganically in focusing on the Nordics markets," Robin Marshall, a managing director at Bain Capital told Reuters.
"We certainly wouldn't rule out going into other countries, particularly those in the Nordic region where we don't have a strong presence currently."
Denmark and Norway accounted for about 88 percent of Nets' revenue in 2012.
Bain and Advent also own WorldPay, another payment processing company, but said they had no plans to merge Nets with other payment industry assets.
Reuters reported this month that Advent, Bain and ATP had entered exclusive talks to buy Nets, which was owned by a group of 186 banks.
It is the third-largest private equity-backed buyout in Europe this year, according to Thomson Reuters data.
The new owners, which intend to own the company for five to seven years, would not indicate any expected return on the investment, but said they expected an exit through an initial public offering (IPO).
Nets was formed in 2010 through the merger of Norwegian Nordito and Danish PBS, and bought Finnish payments company Luottokunta in 2012. The company manages Dankort and BankAxept, Danish and Norwegian domestic card schemes.
Last year it handled more than 6 billion card transactions. Its service supported more than 33 million payment cards and over 500,000 merchants in the Nordics.
It had revenue of 5.96 billion Danish crowns in 2012 and made a net profit of 682 million.
The acquisition will be part-funded with debt provided by a group of banks including JP Morgan, Nordea, UBS , Danske Bank, Deutsche Bank, Mizuho and Nykredit, banking sources said.
The sources told Reuters that Nets' senior debt would comprise of at least 1 billion euros ($1.4 billion) of senior leveraged loans denominated in euros and the local currency.
There will also be subordinated debt which could be in the form of high-yield bonds, mezzanine loans or a second lien facility, they said.
Nordic banks DNB, Nordea and Danske Bank announced separately that they had agreed to sell their stakes in Nets to the private equity firms. The Danish central bank was also a shareholder.
JP Morgan acted as financial advisor to Nets' board of directors. UBS, MHS Corporate Finance and Infima acted as financial advisers to the consortium.
($1 = 5.4161 Danish crowns);($1 = 0.7256 euros)
(Additional reporting by Claire Ruckin, Annabella Pultz Nielsen, Shida Chayesteh and Balazs Koranyi; Editing by Pravin Char)