NEW YORK (Reuters) - President-elect Donald Trump's pick for Treasury secretary Scott Bessant told Congress on Thursday the United States should continue to monitor potential problems in U.S. bond markets, referring to the Wall Street billionaire Howard Lutnick plans to clear U.S. Treasury futures through a clearing agency. British company.

Lutnick's BGC Group brokerage launched a futures exchange last year and plans to add U.S. Treasury futures in the first quarter of this year.

FMX Futures' partnership with London Stock Exchange Group's London Clearing House (LCH) has sparked concerns among some U.S. lawmakers that the U.S. could lose control and oversight of certain Treasury market trading.

The U.S. Treasury bond market is worth approximately US$28 trillion and is the world's largest bond market. It is crucial to the U.S. government's own financing capabilities and global financial stability.

During Bessant's confirmation hearing on Thursday, Senator John Cornyn asked him whether "the proposed entity to clear U.S. Treasury futures at the London Clearing House" would have financial stability implications, alluding to FMX.

"Some believe the Bank of England will be able to contain defaults in this key market, and hopefully that won't happen, rather than the United States," he said.

Bessant said decision-making power in the U.S. Treasury market should remain with the country.

"It's important for the United States, for U.S. Treasuries, that we be able to address any stress issues in U.S. markets," he said, adding that he planned to investigate the issue.

Bessant pointed out that the collapse of Lehman Brothers in 2008, which caused global markets to plummet, was triggered by problems at its British subsidiary.

Lutnick, a Trump supporter, lost to Bessant for the Treasury secretary job but was chosen to head the Commerce Department to lead Trump's trade and tariff strategy.

A spokesperson for FMX said that FMX Futures Exchange has received full approval from the U.S. derivatives regulator the Commodity Futures Trading Commission (CFTC) to list U.S. Treasury futures contracts.

A spokesman for the London-based company said LCH is registered with the U.S. Commodity Futures Trading Commission (CFTC) to clear futures contracts.

The spokesperson added in an emailed statement: "As required by the CFTC, LCH holds all futures customer collateral within the United States to protect such funds and assets belonging to U.S. companies."

(Reporting by Davide Barbuscia in New York; Editing by Nia Williams)