multi-trillion plan to save the eurozone , page-22

The maintenance margin is an estimate of the potential loss (usually at the 99th percentile) on a derivative position between on close and the next. The calculation is made using recent market price movements. It is intended to protect the CME from losses should a clearing member not meet a margin call and potentially leave CME with the obligation to meet payments to the clearing members on the other side of the transaction.

As such these margins will increase with recent market volatility. This is good risk management practice. To suggest that CME would use them to influence market direction is nonsense.