The ES contract and the MES, on one page

The E-mini S&P 500 (ES) is the future on the S&P 500 index listed on CME Globex. The micro (MES) is the same contract divided by ten. The two share the same price, not the same order book. Before reading a book, you need to know which market you are reading, at what time, and against whom; this lesson pins down the contract, the next ones pin down the time and the players.

Three practical consequences

1. You read the ES book, never the MES book. The liquidity, the walls, the icebergs are on ES. MES is for executing at reduced size, not for reading.
2. The quarterly roll shifts liquidity to the next contract on the second Thursday of the contract month, eight days before expiration. The next ones: Thursday, December 10, 2026, then March 11, June 10, September 9 and December 9, 2027. During roll week, check that the chart, the DOM and the options chart all point to the same contract.