(Reuters) -- Stock index futures slid after the market's close on Thursday as JPMorgan Chase & Co said its chief investment office had significant mark-to-market losses since March 31. JPMorgan's stock lost 5 percent to $38.67 in after-hours trading.

S&P 500 futures fell 9.2 points and were below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration of the contract. Nasdaq 100 futures fell 14.75 points.

(Reporting by Edward Krudy; Editing by Jan Paschal)