A "short" position is generally the sale of a stock you do not own. Investors who sell short believe the price of the stock will decrease in value. If the price drops, you can buy the stock at the lower price and make a profit. If the price of the stock rises and you buy it back later at the higher price, you will incur a loss. Figure 2: Bad behavior - The 7 deadly sins to avoid. Averaging down into losing positions. Over-concentration in too few positions. Investing in illiquid positions. Falling in love with a stock, position, or a management team. Excessive use of margin. Over-concentration in one sector. Hubris. a supply of goods kept on hand for sale to customers by a merchant, distributor, manufacturer, etc.; inventory. a quantity of something accumulated, as for future use: a stock of provisions. livestock. Theater. a stock company: a job in summer stock. Finance. the outstanding capital of a company or corporation.