LONDON (Reuters) - Swiss-based trading and mining giant Glencore is selling a bundle of its global oil storage stakes, sources told Reuters, following similar moves by rivals as a boom period for storage shows signs of nearing to an end.

FILE PHOTO: The logo of commodities trader Glencore is pictured in front of the company's headquarters in Baar, Switzerland, September 30, 2015. REUTERS/Arnd Wiegmann/File Photo

Demand for storage exploded following the oil price plunge in 2014 because the abundance of crude for immediate delivery meant traders could make millions by buying oil cheaply and storing it to resell later as prices recover.

As the Organization of the Petroleum Exporting Countries (OPEC) decided to cut oil output at the end of 2016 to prop up prices and help ease the global glut, the market balance began to change.

Today, future prices are no longer trading at a steep premium to immediate prices, thus reducing the appeal of storing oil and prompting some of Glencore’s rivals to reduce exposure to storage assets, including Vitol and Gunvor.

If the sale reaches completion, Glencore will likely end up with minority stakes in the assets. The company owns much of its storage terminal interests via joint ventures and is selling half of these stakes, the sources familiar with the sale said.

A spokesman for Glencore declined to comment.

“It’s an exotic combination of assets with a variety of functions, mainly storage. It’s most, if not all, of Glencore’s global liquid storage,” one source said.

The portfolio includes assets in Argentina, Belgium and Madagascar, the source said.

“As a bundle it would appeal to someone looking for an entry point to certain countries,” the source added.

The source said the assets were generating EBITDA or core earnings of around $75 million a year.

Glencore and other trading houses with large storage assets compete with listed storage firms such as Vopak NV, Magellan Midstream Partners LP and Kinder Morgan Inc.

Given a limited number of listed storage firms, price to earnings (P/E) ratios in the sector tend to vary significantly between as low as 7 and as high as 15, which in theory could give Glencore’s storage assets a value of between $0.5-$1.1 billion.

Lately, some of Glencore’s competitors have been divesting similar assets. Vitol, the world’s largest independent oil trader, sold a 50 percent stake in its terminal and infrastructure company VTTI to Buckeye Partners in October last year.

Swiss trader Gunvor is looking to sell a stake in a Rotterdam storage terminal and Trafigura is considering an IPO for downstream company Puma Energy, in which it holds a major stake.