U.S. Senate investigators probing an insider trading case at $13 billion hedge fund SAC Capital Advisors will also look at its options trading, The Wall Street Journal reported, citing people familiar with the situation.

The Financial Industry Regulatory Authority (FINRA) has informed the Senate Judiciary Committee head Charles Grassley about 20 instances of suspicious trading at the hedge fund founded by Steven Cohen.

The investigation is taking in trade in stocks including healthcare company shares affected by clinical trials or information communicated at industry conferences, the paper said.

Senate investigators are in talks with the U.S. Securities and Exchange Commission and the Department of Justice over SAC Capital's trades, the Journal reported.

FINRA, SAC Capital and Senator Grassley could not be reached immediately for comment outside of normal U.S. business hours.