IMM dates

The IMM dates are the four quarterly dates of each year which certain money market and Foreign Exchange <a href="/facts/Futures_contract/4SD3dKty">futures contracts</a> and <a href="/facts/Option_(finance)/5gJFXV3X">option</a> contracts use as their scheduled <a href="/facts/Maturity_date/zbEuul9J">maturity date</a> or <a href="/facts/Termination_date/zbEuul9J">termination date</a>. The dates are the third Wednesday of March, June, September and December (i.e., between the 15th and 21st, whichever such day is a Wednesday). 
These contracts stop trading the Monday preceding the third Wednesday of a March quarterly cycle. <a href="https://www.cmegroup.com/education/courses/understanding-stir-futures/understanding-imm-price-and-date.html">see CME Tutorial</a>
IMM stands for the <a href="/facts/International_Monetary_Market/JpLQfeQu">International Monetary Market</a>.
This choice of date – middle of month and middle of week – minimizes issues with <a href="/facts/Date_rolling/1qx5tqQd">date rolling</a>, as holidays are very unlikely to make the closest business day in another week or other month.
The term is also used for the conventional quarterly termination dates of <a href="/facts/Credit_default_swap/PPsAwQhs">credit default swaps</a>, which fall on 20 March, 20 June, 20 September and 20 December – note that these may fall on a weekend. These are not precisely the IMM dates, but they fall close to them and thus are also referred to as "IMM dates", by abuse of language.

IMM dates open-in-new

IMM dates