LONDON (REUTERS) - The London Metal Exchange has made an informal approach to the Baltic Exchange to acquire the entire business, two sources familiar with the matter told Reuters.

"It's an informal approach," one source said, adding that a potential offer could be based on three times the net asset value of the Baltic. "The LME has made strong overtures to the Baltic," the second source said.

The LME and Baltic Exchange declined to comment.

The London Metal Exchange is the world's oldest and biggest market for trading industrial metals. Its settlement prices are used as benchmarks by producers and consumers of industrial metals such as copper and aluminium.

The Baltic Exchange, based in London, produces daily benchmark rates and indices that are used to trade and settle freight contracts as well as data used in the freight derivatives market. It also owns a freight derivatives platform called Baltex.