LONDON, Oct 9 (Reuters) - The London Metal Exchange (LME) is looking at its fee structure to address the fact that over-the-counter (OTC) trading is cheaper than trading on the exchange, the LME's chief executive said on Monday.

The 146-year-old LME was forced to halt nickel trading and cancel all deals in March last year after a wild spike in prices caused partly by large OTC short nickel positions.

Since then the exchange, the world's oldest and largest market for industrial metals, has imposed measures requiring members to report all OTC positions.

The LME has said that the market would benefit from more trading migrating to its electronic platform rather than to telephone-based trading or OTC markets.

During a panel discussion on Monday on the future of the LME nickel contract, which saw trading volumes tumble after last year's crisis, LME CEO Matthew Chamberlain noted that people sometimes ask him why OTC trading is cheaper than on the LME.

"That's one area we're looking at," Chamberlain said, giving no details.

The LME requires institutions that book OTC trades that use LME prices as a benchmark to pay a fee to the LME of $1.14 per equivalent LME lot, which compares to all-in fees of $2.70 per lot paid for exchange trading.

The LME is owned by Hong Kong Exchanges and Clearing Ltd. (Reporting by Eric Onstad; Editing by Sharon Singleton)