UPDATE 2-Turkey's Yildirim buys stake in Gemport from Isbank

* Deal reached after drawn-out negotiations

* Stake valued at $350-400 mln - analyst

* Port is Turkey's 10th biggest

(Recasts with Gemport statement)

By Birsen Altayli

ISTANBUL, Oct 2 (Reuters) - Turkish industrial group Yildirim Holding is buying a majority stake in lender Isbank's

port unit Gemlik Liman (Gemport), striking an 11th-hour deal to strengthen its position in the country's fast-growing ports industry.

Gemport said on Tuesday Yilport, a unit of Yildirim Holding, had signed an agreement to buy a 54 percent stake in Gemport from Isbank. It gave no financial details.

"The decision was not made until the last minute after eleventh-hour negotiations," a source close to the matter told Reuters.

A source close to the situation had previously said that Turkish army pension fund Oyak had agreed to buy Gemport.

"We estimate a roughly $350-400 million transaction value," Oyak Securities, a unit of the pension fund, said in a research note after Isbank announced late on Monday it was selling the stake.

Gemport is located near Istanbul, south-east of the Marmara Sea, and has an annual container storage capacity of 600,000 20-foot equivalent units (TEU), according to its website. TEU is a standard unit for the cargo capacity of container ships and container terminals.

Gemport was the 10th biggest port in Turkey in terms of handling capacity as of 2009, according to an Ernst and Young report.

Yildirim Holding was founded in 1963 and is active in businesses including mining, port management, construction, ship building and fertilizers.

Turkey has a coastline of more than 8,000 km and is strategically positioned between Europe and Asia. The country has around 175 ports, mostly privately operated and concentrated around Istanbul, its largest city.

Turkey does 88 percent of its trade via its ports, according to Ernst and Young. Its overall handling capacity was 6.6 million TEU in 2011, three times that of Greece, according to independent market monitor Drewry Shipping Consultants.

(Writing by Seda Sezer; Editing by Nick Tattersall and Mark Potter)

((seda.sezer@thomsonreuters.com)(+90 212 350 7051)(Reuters Messaging: seda.sezer@thomsonreuters.com))