Buy Minus

Buy Minus refers to an order to buy a stock when it's below its current price.

The grammar is weird here, but you could remember it as "Buy when it's minus X dollars." A trader or investor might place this order if they're anticipating a drop in price, and want to be first in line to buy when it drops.

Generally, a couple things must happen for this order to be placed. The price of the share must be below the current market price, and the last trade on the share has to have been a minus buy as well.

It's like seeing a big screen TV on clearance at a department store, and knowing they have plenty in stock to unload before the new holiday inventory arrives (you have friend that works there, so you've got the inside scoop). You might decide, knowing they have a supply on hand and a limited time to sell it, to wait to buy until they drop the price a bit more. You know they might sell out faster than you anticipate, and you might not get a TV at all, but if you do...you'll get it at the price you wanted.

See Uptick Rule.