U.S. Senator Chuck Grassley asked the Securities and Exchange Commission for information relating to its stock-trading inquiry into hedge fund SAC Capital Partners LP.

In a letter sent today, Grassley of Iowa, the senior Republican on the Judiciary Committee, asked SEC chairman Mary Schapiro to explain how the regulator has handled allegations of suspicious trading. Grassley’s office has said he has received about 20 examples from the Financial Industry Regulatory Authority of possible insider trading involving SAC Capital.

His letter asks the SEC how it resolved the referrals, how the number of referrals compares to similar firms, and whether the agency drafted a Wells Notice related to the situation.