Celler-Kefauver Act Closes Merger Loopholes, Strengthens Government Power to Block Anticompetitive Consolidation

Congress passed the Celler-Kefauver Anti-Merger Act, championed by Representative Emanuel Celler (D-NY) and Senator Estes Kefauver (D-TN), fundamentally strengthening the Clayton Antitrust Act of 1914 and giving the government powerful new tools to prevent anticompetitive mergers. The Act closed critical loopholes that corporations had exploited for decades: while the Clayton Act prohibited stock acquisitions that reduced competition, shrewd businessmen simply bought competitors’ assets instead. Celler-Kefauver prohibited asset acquisitions if they substantially lessened competition. More importantly, it expanded enforcement beyond horizontal mergers (competitors combining) to vertical mergers (companies at different supply chain stages) and conglomerate mergers—giving regulators authority to block any merger threatening competitive markets. Celler and Kefauver effectively leveraged Cold War fears about concentrated power, arguing that unchecked corporate consolidation threatened American democracy itself. President Harry Truman, a longtime antitrust advocate, strongly supported the bill and appointed enforcement hawks to the FTC. The Act represented the high-water mark of merger enforcement authority—power that would be systematically dismantled starting with Reagan’s 1982 Merger Guidelines. Where Celler-Kefauver gave government the tools to block vertical and conglomerate mergers, Reagan antitrust chief William Baxter would declare ’there is no such thing as vertical merger’ and refuse to enforce these provisions, effectively repealing the law through administrative fiat rather than Congressional action.