What is Market Implied Open? Definition, Formula, and Example
The market implied open is the expected opening price of an index or stock derived from futures contracts trading before the cash market opens.
What is Market Implied Open
The market implied open is the expected opening price of a cash index or stock derived from futures contracts trading before the cash market opens. It tells traders where the market is likely to open based on overnight futures prices adjusted for dividends, interest, and time to expiration.
How it's Calculated
Formula: Implied Open = Futures Price × e^((r - q) × t) - Dividend Adjustment
Where r is the risk-free rate, q is the dividend yield, t is time to futures expiration in years, and the dividend adjustment subtracts expected dividends before expiration. Practitioners often use the cash-and-carry relationship reversed: spot equals futures discounted for carry.
Worked Example
The S&P 500 futures trade at 5,100 before the cash market opens. The cash index closed at 5,080. Interest and dividend adjustments imply a fair value of 5,090. The implied open is 5,090, suggesting the cash index will open 10 points above its prior close.
When Traders Use It
Traders compare the implied open to the prior close to gauge overnight sentiment and order flow. A large gap between fair value and the previous close suggests program trading at the open. Index arbitrageurs buy or sell baskets against futures when the deviation exceeds transaction costs. the live scanner
Limitations / Common Misconceptions
The implied open is an estimate, not a guaranteed opening price. News released after futures settle but before the cash open can move the actual opening print. It assumes continuous arbitrage and ignores liquidity constraints at the opening cross. The calculation varies by index methodology and does not apply to individual stocks without liquid futures.