The Form 4 doesn't say how that "error" occurred.
However, the second footnote on Form 4 says that at some point after getting the performance share units in 2013, Pearson returned to Valeant "the value of such shares on the date of delivery (plus interest)."
In connection with Pearson returning that value, Valeant then credited him with the 502,996 "vested share units" that are the subject of the Form 4 filing, according to the footnote.
SIRF's report notes that Valeant's stock was trading at $84.47 per share on May 24, 2013, the day that the company erroneously awarded Pearson the restricted share units. On March 11, 2014, the day that Pearson received the same number of restricted shares to compensate him for having returned to Valeant the value of the erroneous RSU award, Valeant was trading at $139.96 per share.
SIRF's article points out that if one assumes that Pearson wrote Valeant a check to compensate the company for the initial share award, it would have been for $42.48 million. That is almost $28 million less than the $70.39 million the same number of shares were worth in March 2014, when he received the second award.
However, Valeant's stock is worth a lot less than that now. The shares were trading in the mid-$70s on Thursday.
When CNBC reached out for comment, Laurie Little, senior vice president for investor relations at Valeant, said, "The fact is that the misdelivery of shares to Valeant's CEO was publicly disclosed in an SEC filing on March 13, 2014."
"As disclosed in our public filing, the shares that Mike Pearson received in error were fully vested as of May 24, 2013, based on achievement of the applicable performance criteria, and Mr. Pearson repaid the value of the shares he received plus interest."
A Valeant spokeswoman confirmed it was a "clerical error." She added the error occurred because Valeant was following procedures used for other company employees in which performance share units vest and settle concurrently. "Mr. Pearson's then-current compensation agreement had a provision requiring delayed settlement of vested shares until 2019. He was the only Valeant employee with that provision, and the shares were mistakenly delivered under the procedures used for other employees. The error was discovered in the fourth quarter of 2013 and corrected in that same quarter by Mr. Pearson returning to Valeant the taxable income incorrectly paid to him."
The spokeswoman added: "The taxable amount was determined in accordance with Valeant's standard practice of valuing stock at the closing price the day prior to vesting. In accordance with the corrections procedures outlined by the Internal Revenue Code, Mr. Pearson paid this amount to the company, plus interest. Pursuant to the corrections procedure, Mr. Pearson could have repaid the taxable income either in cash or by returning a number of shares equal to the value delivered in error. Mr. Pearson elected to repay cash."
Goldman sold 1.3 million Valeant shares on Nov. 5 after telling Pearson it needed to do so if he didn't repay the balance of that loan. The sale by Goldman contributed to a 14 percent drop in the stock that day.
UDPATED: This story was updated to include a full statement from a Valeant spokeswoman.