* Concardis owners eye complete or partial sale - sources
* Investor sought for investments in new technologies - sources
* Deutsche Bank, Commerzbank expected to sell stakes - sources (Adds names of potential bidders)
By Arno Schuetze and Alexander Hübner
FRANKFURT, Oct 6 (Reuters) - German banks are putting jointly-held payments group Concardis up for sale, with the group seeking a partner for investments in new technologies, people close to the matter said on Thursday.
Concardis offers card payment terminals as well as payment technology for e-commerce groups and may appeal to peers as well as to private equity companies, the people said.
It posted core earnings of 33.9 million euros ($37.9 million) and a net profit of 24.2 million euros on sales of 480 million euros last year. It said in its annual report that core earnings were expected to rise 7 percent this year.
If valued in line with listed peers, which trade at 10-15 times their expected core earnings, Concardis may fetch 360-550 million euros.
German savings banks and privately-held banks each own 39 percent of Concardis. Another 20 percent is held by cooperative banks.
Shareholders including Deutsche Bank, Commerzbank and Unicredit have signaled they want to sell out, while some of the other lenders may stay partially invested, one of the sources said.
Concardis has already received a number of expressions of interest from buyout groups as well as other payment systems suppliers. It is currently preparing data for potential bidders and is expecting to receive first offers by early November, the source said.
Private equity groups with expertise in financial assets such as Advent and Bain - the former owners of Worldpay - as well as Permira and Warburg Pincus are expected to bid for Concardis, the sources said.
It may also appeal to peers such as France's Ingenico and Atos, U.S.-based First Data or Germany's B+S.
Concardis, which is working with KPMG and Deloitte but without the help of an investment bank, declined to comment, as did its owners.
$1 = 0.8950 euros Reporting by Arno Schuetze and Alexander Huebner; Editing by Mark Potter