Kiting
Used in banking to refer to the practice of depositing and drawing checks at two or more banks and taking advantage of the time it takes for the second bank to collect funds from the first bank.
Also refers to illegally increasing the face value of a check by changing the numbers on the check.
In the context of securities, refers to the manipulation and inflation of stock prices.

Kondratieff Wave
An economic theory of the Soviet economist Kondratieff stating that the economies of the western world are susceptible to major up-and-down "supercycles" lasting 50 to 60 years.

Keynesian economics
An economic theory of British economist, John Maynard Keynes that active government intervention is necessary to ensure economic growth and stability.

Kickback
In the context of finance, refers to compensation of dealers by sales finance companies for discounting installment purchase paper.
In the context of contracts, refers to secret payments made to insure that the contract goes to a specific firm.

Killer bees
Those who aid a company in fending off a takeover bid, usually investment bankers who devise strategies to make the target less attractive or more difficult to acquire.