The civil inquiry is also looking at whether an "expert network" business that is part of an investment bank leaked nonpublic information to traders.
The number of Cougar shares owned by SAC rose to 632,291 as of March 31, 2009, from 7,800 at the end of 2008, the Journal said, citing SEC filings. Johnson & Johnson announced its Cougar deal on May 21 of that year.
Representatives of SAC, Johnson & Johnson and Cougar declined to comment to the Journal.
The SEC has not accused SAC or the other entities involved in the Cougar probe of wrongdoing. It is unclear whether the inquiries, which have been ongoing for more than a year, will result in any charges, the Journal said.
SAC, Johnson & Johnson, SEC and Cougar were not immediately available for comment when Reuters contacted them.
(Reporting by Maneesha Tiwari in Bangalore; Editing by Lisa Von Ahn)