The US Securities and Exchange Commission (SEC) said on Friday it is suspending enforcement of the costliest requirements of its “conflict minerals” rule, after a court remanded it back to the regulator because part of it violates the US Constitution. Acting SEC chairperson Mike Piwowar, a Republican, said he has asked staff for a recommendation on how to proceed with the rule, which requires companies to disclose if their products contain certain minerals from a war-torn part of Africa.