Don't fight the tape

Don't fight the tape is a term used in finance. It means do not bet or trade against the trend in the financial markets, i.e., if the broad market is moving up, do not bet on a downward move. The term "tape" refers to the ticker tape used to transmit the price of stocks. It is analogous to the trader's maxim, "The trend is your friend."

It is a form of peer pressure, groupthink and self-fulfilling prophecy.