LUXEMBOURG (Reuters) - The European Investment Bank proposed on Monday to help close the funding gap and retain the most innovative start-up companies looking to grow in Europe through support for the EU venture capital and private equity markets.

The initiative, presented by the bank to finance ministers at a meeting in Luxembourg, is part of the EU's push to develop its capital markets and be attractive for innovative start-ups that now often relocate to the United States where finding financing is easier.

The EIB said in a statement that it would finance the scale up of European unicorns -- companies with unique ideas and growth potential -- by expanding the European Tech Champions Initiative, a fund of funds launched last year that provides late-stage capital to European innovators.

The EIB, which is owned by the EU's 27 governments, also offered to boost equity and venture debt investments and create a new dedicated fund for financing acquisitions and listing of tech start-ups by European firms.

"We're talking about ensuring that European companies, technologies that are born in Europe, stay in Europe, and that we invest in Europe's champions, in Europe's unicorns, that we reinforce Europe's competitiveness through a stronger capital market," EIB president Nadia Calvino said.

The funding strategy is also meant to help Europe stay competitive against China and the United States in new, climate-friendly technologies the EU needs to meet its ambitious climate goals of zero net CO2 emissions by 2050.

"There's unanimous agreement at the technical level on the need to deepen Europe's capital markets and to reinforce the integration of our capital markets," Calvino said. "This will reinforce Europe's competitiveness and fund European successful companies. There is also political momentum right now."

(Reporting by Jan Strupczewski; Editing by Mark Porter)