transactions (sales and purchases) having the objective of supplying commodities (goods and services)

do business; offer for sale as for one's livelihood

trading in bonds (usually by a broker on the floor of an exchange)

a trading technique involving large blocks of stock with trades triggered by computer programs

sale of securities or commodity futures not owned by the seller (who hopes to buy them back later at a lower price)

the purchase of securities or commodities by a short seller to close out a short sale

buying or selling corporate stock by a corporate officer or other insider on the basis of information that has not been made public and is supposed to remain confidential