The Clayton and FTC acts.
This sculpture, one of a pair outside of the Federal Trade Commission Building in Washington, is entitled "Man Controlling Trade." It was completed for the FTC Building in 1942 by New York sculptor Michael Lantz.
The Clayton Act
Section 7.
Acquisition of competing companies  
Explicitly subjected stock-purchase acquisitions to scrutiny.  Asset loophole closed by Celler-Kefauver Act (1950).