Munich  - Dutch bank ING Direct announced plans Monday to launch a public tender offer for Interhyp AG, Germany's largest independent residential mortgage distributor.

The bank said it plans to offer 64 euros (98.5 dollars) per share, valuing the company at 416 million euros.

The founders and co-chief executives of Interhyp, Robert Haselsteiner and Marcus Wolsdorf, have pledged to sell their 32 per cent stake in the company, ING Direct said.

The news sent the mortgage broker's shares soaring on the Frankfurt stock exchange. At noon they were up 36.68 per cent at 67 euros.

ING Direct said it intends to launch its public offer in June, which will last for at least four weeks.

"This acquisition is in line with ING Direct's strategy to strengthen and expand its range of simple products in savings, mortgages, payment accounts and investment services," said chief executive officer Dick Harryvan.

Since its foundation in 1999, Interhyp has been offering residential mortgages from over 50 banks, mostly via internet and telephone.

With more than 38,000 closed mortgages and a distributed mortgage volume of 5.7 billion euros in 2007, it is by far the largest independent residential mortgage distributor in Germany.

An Interhyp spokesman said no cuts were planned in the company's 470 staff. (dpa)