Aldermore, partly owned by private equity fund AnaCap Financial Partners, focuses on lending to small and medium-sized businesses and homeowners.

The offer will consist of 75 million pounds of new shares, plus an undetermined amount of existing shares, it said on Monday.

Aldermore is part of a wave of so-called "challenger banks" to opt for a listing, with OneSavings OSBO.L and TSB TSB.L floating earlier in 2014, as they seek to wrest market share from major high-street lenders such as Lloyds LLOY.L, Royal Bank of Scotland RBS.L and Barclays BARC.L.

Virgin Money IPO-VMH.L is also expected to float this year.

Aldermore said first-half profit leapt 249 percent to 18.6 million pounds, while lending to businesses and homeowners hit the 4 billion-pound mark.

"We're raising more capital to put more fuel in the tank," said Chief Executive Officer Phillip Monks.

The company does not intend to pay a dividend in the near term, but will consider doing so from 2017 depending on growth opportunities, it said.

Credit Suisse CSGN.VX and Deutsche Bank DBKGn.DE are leading the listing, while Nomura and Numis are co-lead managers. Lazard LAZ.N is advising.

(Reporting By Freya Berry; editing by Susan Thomas)