A Sunday Times article reported that the lender "has begun quietly sounding out investors, with the aim of going public next month".
The company, owned by the private equity group AnaCap, was expected to have begun trading on the 17th of October, and hoped to raise around £75m in capital from the launch.
The challenger bank had set a target share price range between 217p and 265p per share, but is now expected to lower the price to attract investment.
Aldermore has around £4bn in loans outstanding, and reported pre-tax profits of £18.6m for the half-year to 30 June, up from £5.3m a year earlier.
Virgin Money also delayed floatation plans in October, before lowering its share prices and successfully floating in November.