A fall in the price of a stock, sector, or market, or investor sentiment that assumes a fall will happen soon. A bear tack is usually used to describe bearish movement in the short to medium term.

In sailing, a tack is a maneuver in which a boat turns its bow to put the wind on the opposite side of the boat. A bear tack is a buzz word that is derived from this sailing term to explain a change in movement of a security or index.