The president announced new loan guarantees at a White House event that appeared intended to reassure a group that has found itself caught in the cross hairs of some of his major policies.
Mr. Musk's participation was notable because it is rare for a private citizen to be on a call between heads of state. It also suggests that Mr. Musk is back on better terms with the president.
Tehran has effectively closed off the critical waterway, turning back container ships on Friday, and Iranian lawmakers are considering whether to charge fees to pass.