It’s no accident that Pershing Square chief Bill Ackman used the Securities and Exchange Commission’s beneficial ownership reporting requirements to his advantage in his joint bid with Valeant for Allergan. As Bloomberg reported Tuesday, Ackman was the ringleader three years ago of a full-court press to keep the rules just as they are.

Current rules provide that investors who buy 5 percent or more of a company have 10 days to report that fact to the SEC. Though in 2010, Bloomberg noted, the SEC gained the flexibility through the Dodd-Frank Act to shorten that 10-day window, in 2011 Ackman “recruited a group of large investors” who persuaded the SEC to leave the rule alone, even though there were indications that the SEC thought it should move to shorten it.