Editing Futures contract (section)

===Expiry===
Expiry (or "expiration" in the U.S.) is the time and the day that a particular delivery month of a futures contract stops trading, as well as the final settlement price for that contract. For many equity index futures and interest rate futures as well as for most equity (index) options, this happens on the third Friday of certain trading months. On this day the ''back month'' futures contract becomes the ''front-month'' futures contract, and the ''front-month'' futures contract becomes the ''back month'' futures contract. 

For example, for most [[Chicago Mercantile Exchange|CME]] and [[Chicago Board of Trade|CBOT]] contracts, at the expiration of the December contract, the March futures become the nearest contract. During a short period (perhaps 30 minutes) the [[underlying]] cash price and the futures prices sometimes struggle to converge. At this moment the futures and the underlying assets are extremely liquid and any disparity between an index and an underlying asset is quickly traded by arbitrageurs. At this moment also, the increase in volume is caused by traders rolling over positions to the next contract or, in the case of equity index futures, purchasing underlying components of those indexes to hedge against current index positions. 

On the expiry date, a [[Europe|European]] equity arbitrage trading desk in [[London]] or [[Frankfurt]] will see positions expire in as many as eight major markets every approximate half hour. Exchanges implement strict limits on how much exposure an entity may have closer to expiration as an effort to avoid any volatility around final settlement.