As of right now, IB has apparently updated the listed tabular intraday margins. Of course it is unknown whether their web updates are the same as the margins they are actually applying.
IT'S WORSE THAN THEIR FORMULA SUGGESTED
Their formula is:
"We feel the current market volatility warrants additional margin to ensure accounts have adequate financial capacity to handle sharp, adverse movements. Accordingly, effective August 6 2007 and until further notice, IB will apply the following logic to determine the intraday margin:
Effective Intraday Margin is equal to the table value (listed below) or 4% of the contract value (price times contract multiplier). If this amount exceeds the normal overnight margin as listed on the below table, it will be capped at the overnight amount. Mathematically, this can be expressed as:
IntradayMargin = MIN( overnightMargin, MAX(tableMargin,4%*contractValue) ) "
Unless I can't calculate...
ES should be around $2948, by their formula, but the table pegs intraday = overnight = $3500.
YM should be around $2672, but they peg it up to $2813.
Agricultural futures ECBOT like corn, wheat also intraday=overnight generally.
metals, etc. generally the same thing.
Now we all live in a "safer", if less leveraged, trading world

FS