Some of the owners of the joint venture that operates Istanbul’s giant new airport hired Lazard Ltd. to sell their stake in the $11 billion hub, according to people with knowledge of the matter.

The U.S. investment bank is working with some members of the IGA consortium to provide a valuation of the airport and manage discussions with potential buyers, the people said, asking not to be identified because the process is confidential.

Vinci SA, Aeroports de Paris and its Turkish unit TAV Havaliamanlari Holding AS, and Ferrovial SA are among interested parties, two of the people said.

TAV rose as much as 3.7 percent to 23.38 liras in Istanbul, the most since April 1. Turkish Airlines, which is using the airport as its new hub, added to gains to rise as much as 4.8 percent to 11.8 liras, the most since April 4.

IGA has the biggest corporate debt load in Turkey after borrowing about 5.7 billion euros ($6.4 billion). Payments over the 25-year lease to operate the airport total 22.1 billion euros, or 1.1 billion euros a year.

The high cost of the lease to operate the new airport is likely to deter potential buyers, according to one of the contacted parties, who spoke under the condition that they not be named.

“The market is not likely to welcome the news given the scale of the concession payments of the airport and heavy leverage,” said Deniz Invest, an Istanbul-based brokerage, in an emailed comment on TAV Havalimanlari’s interest in the deal.

Delayed Opening

Located 20 miles outside Istanbul on the Black Sea coast, the field has two operational runways and occupies an area larger than Manhattan. It opened to international commercial flights in April after several delays. The outlet replaced Ataturk airport, which was operated by TAV Havalimanlari before it was shut down last month. The new airport is designed to eventually serve 200 million passengers when all six runways are operational.

Five Turkish builders - Cengiz Insaat, Limak Holding, Mapa Insaat, Kalyon Insaat and Kolin Insaat - each with equal stakes at the time, won the right to build and operate the airport. Kalyon Insaat now has a 35% stake and Cengiz Insaat a 25% holding after Kolin Insaat sold its 20% earlier this year. Limak and Mapa each retain a 20% stake.

An IGA spokesman said the company has no plans to sell a stake. Spokesmen for Vinci, ADP and TAV all declined to comment. A spokeswoman for Lazard didn’t immediately respond to an email. Spokespeople for Ferrovial SA weren’t immediately available for comment.