Mutual funds report performance in the form of a holding period return (HPR) over standardized horizons. Changes in HPRs are equally influenced by new and previously reported stale returns which enter and exit the horizon. Investors appear unable to differentiate between the joint determinants, reacting with equal strength to both signals. Stale performance chasing is amplified for funds which promote performance via advertising and is more pronounced during periods of uncertainty in financial markets. Fund managers exploit this behavior by preferentially timing fee increases to align with periods of heightened investor demand resulting from stale performance chasing.