Universal banks may have contributed to the economic boom and bust cycle of 1921-33 by encouraging speculative behavior and unsustainable investments. Commercial banks played a major role in the securities markets during this period, leading to heavy debt burdens and risky investments that collapsed in the 1929 recession. The relaxation of legal rules allowed banks to expand their financing through various channels, ultimately promoting speculative ventures. The Glass-Steagall Act was enacted in 1933 to address these conflicts of interest and prevent future financial crises.