William Ward Pigman was an American citizen and member of the Communist Party of the United States who worked in the National Bureau of Standards in the 1930s. He was a member of the "Karl group" of spies for Soviet Military Intelligence (GRU).
Pigman supplied documents to J. Peters for Soviet intelligence as early as 1936. In his book, Witness, Whittaker Chambers refers to Pigman using the pseudonym "Abel Gross". The Gorsky Memo cites him as "114th".
- Allen Weinstein, Perjury: The Hiss-Chambers Case (New York: Random House, 1997).
- Alexander Vassiliev, Untitled Notes on Anatoly Gorsky’s December 1948 Memo on the Failed American Networks (2003).