Other Bear Stearns executives also contend during a federal hearing that they closely monitored the firm's risk and tried to reduce exposure but that ultimately a rumor-fed run caused the downfall. One questioner calls their testimony a 'pathetic mythology.' Former executives at Bear Stearns Cos. on Wednesday defended the investment bank's practices and said the firm's collapse was caused by an unstoppable run fed by rumors as the financial markets began spiraling downward in 2008.