Credit Suisse has been brought in by London City airport to advise is on a potential sale, according to reports.
Reuters quoted sources close to the deal, saying the sale for as much as £2 billion could be concluded as soon as this year.
London City is majority-owned by GIP Global Infrastructure Partners, which also owns Gatwick and Edinburgh airports.
GIP bought a 75% stake in City Airport for £742 million in 2006. Oaktree Capital Management holds the rest.
Reuters said both owners have agreed to the disposal but none of the parties involved in the deal would officially comment on the confidential talks.
London City is expected to attract interest in infrastructure funds and also rival airport operators.
The airport expects to serve six million passengers by 2023 and reports earnings of £45.8 million in 2014, an increase of nearly 10% on the previous year.