The simultaneous expirations generally increases the trading volume of options, futures and the underlying stocks, and occasionally increases volatility of prices of related securities.
en.wikipedia.org Speculators on futures price fluctuations who do not intend to make or take ultimate delivery must take care to zero their positions prior to the contract's expiry.
en.wikipedia.org New trading instruments such as swaps, futures, and options have grown up.
en.wikipedia.org Until about 1710, only physical rice was traded but then a futures market emerged where "coupons", promising delivery of rice at a future time, began to be issued.
en.wikipedia.org Agricultural commodities, however, remain in the opposite type of market, backwardation, which is more desirable for traders who are buying futures contracts.
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