The White House is expected to extend a waiver of the century-old Jones Act in the coming days, sources say, reaching for one of the few tools it has to try and hold down gasoline prices as President Donald Trump escalates his attacks on Exxon Mobil and Chevron for making “too much money”, Reuters reports.

The Jones Act requires cargo moving between US ports to be carried on ships built in the US, owned by US companies and crewed by American workers, and the waiver aims to lower gas prices by increasing shipping flexibility and reducing transport bottlenecks.

The oil industry expected an extension by the end of July. But administration officials have continued meeting with maritime industry representatives and lawmakers over potential changes to narrow the scope of the waiver while preserving flexibility to move critical fuel supplies, according to three people familiar with the discussions who requested anonymity because they are not authorised to speak publicly.

The current waiver is set to expire on August 16 and has already become the longest suspension of the Jones Act rules in the programme’s history.

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