By Douglas Gillison (Reuters) -Wall Street’s top regulator was the victim of “SIM swapping,” a technique internet fraudsters use to seize control of telephone lines, when its account on the social media platform X, formerly known as Twitter, was hacked earlier this month, the U.S. Securities and Exchange Commission said on Monday. The SEC also said that, six months prior to the attack, staff had removed an added layer of protection, known as multi-factor authentication (MFA), and did not restore it until after the Jan. 9 attack. As anticipation mounted for the agency’s approval of exchange-tra…