Gap Risk - When Prices Jump Past Your Stop

By EC Assets Research Team, Derivatives Research · Published 29 October 2026

Gap Risk: Gap risk is the risk that a price moves from one level to another without trading in between, so that stop orders, hedges and liquidation triggers execute far beyond the level at which they were set. It turns a loss that was planned and capped into one set by the next available price.

What Gap Risk Is

Gap risk is the risk that a price moves from one level to another without trading at any point in between. Markets close overnight and at weekends, announcements land outside trading hours, exchanges halt trading in extreme moves, and liquidity providers step back when uncertainty spikes. In each case the next price can be far from the last one, and anything designed to act at a level in between acts only at the next price.

That distinction matters because most risk controls are dynamic. A stop-loss, a delta hedge, a margin liquidation and a portfolio-insurance rule all work by trading as prices move, and all assume that prices pass through every intermediate level. A gap removes that assumption. The loss is then set by the size of the jump, not by the level at which the control was placed.

In option pricing the same phenomenon is called jump risk. Merton (1976) added jumps to the continuous price process of Black and Scholes precisely because a hedge that is rebalanced continuously cannot replicate an option whose underlying jumps.

How It Works

A position sized by its stop distance loses position × gap rather than position × stop when the price gaps through the stop. The planned loss becomes a lower bound, not a limit. Kaminski and Lo (2014) show that whether a stop-loss rule adds or subtracts value depends on how returns evolve, which makes it a bet on the return process as much as a risk control.

Portfolio insurance shows the mechanism most cleanly. Constant proportion portfolio insurance, analysed by Black and Perold (1992), holds a risky exposure equal to a multiplier m times the cushion, the value V above a protected floor F:

$$E = m \times (V - F)$$

When the risky asset falls by d before the portfolio can trade, the loss is E × d, and the floor is breached whenever d exceeds 1/m. With continuous trading the strategy never breaches the floor. With jumps, Cont and Tankov (2009) show, both the probability and the expected size of a breach rise with the multiplier.

Worked Example

A portfolio of 100 protects a floor of 80, so the cushion is 20. The table shows the exposure each multiplier produces and what a single uninterrupted fall of 25 percent does to it.

Exposure above 100 is leveraged; the fall happens before any rebalancing, as in a gap.

Higher multipliers capture more of a rally and look better in calm markets, which is why they are tempting. They also shrink the jump the structure can absorb, from a third of its value to an eighth. If a bank has guaranteed the floor, the 20 points lost below it at a multiplier of 8 are the bank's, not the investor's, and that is the gap risk a guarantor has to price and hedge.

Real gaps have been larger than most plans allow. On 15 January 2015 the Swiss National Bank discontinued its minimum exchange rate of 1.20 francs per euro; EUR/CHF briefly traded around 0.85, and stops resting just below 1.20 were filled far below their levels. On 5 February 2018 the VIX rose from 17.31 to 37.32, a rise of 115.6 percent and the largest one-day increase in Cboe's daily history since 1990. XIV, an exchange-traded note paying the inverse daily return of short-term VIX futures, lost 96.3 percent of its value, triggered its issuer's acceleration clause and was redeemed.

When It Applies (and Limitations)

Wherever protection depends on trading. Stop-based position sizing, short option positions such as an iron condor, leveraged and inverse products that rebalance daily, margin loans and portfolio insurance all carry gap risk. Positions protected by options already owned do not, because their payoff needs no trade at the moment of the jump.

Gaps cluster. They are most frequent when volatility is already high and liquidity thin, the same conditions in which tail risk and correlations rise. A gap allowance calibrated in calm markets understates the risk when it matters.

Size is hard to estimate. Gaps are rare, and the largest ones, such as the removal of a currency floor, have no precedent in the instrument's own history. Historical frequencies are a lower bound; scenario analysis is the more honest tool.

Liquidity can create a gap without news. A market that trades continuously can still move several percent between consecutive trades when order books empty, so continuous trading hours do not rule it out.

Why It Matters for Institutional Investors

Risk budgets should assume the gap. Sizing a position so that its realistic gapped loss, not its stop-out loss, fits the budget is the only way to make a loss limit binding. With leverage, the same gap consumes a multiple of the capital it would otherwise.

Short convexity hides it. Strategies that sell options or rely on frequent rebalancing earn steady returns between gaps and give them back in one step, which is why their maximum drawdown often arrives in a single session.

It is priced where it is visible. The steep downside skew of equity index options reflects, in part, demand for protection that works in a jump. That protection is expensive in calm markets, which is exactly why the decision to carry gap risk unhedged should be taken explicitly rather than by default.

References

1. Cont, R., & Tankov, P. (2009). Constant Proportion Portfolio Insurance in the Presence of Jumps in Asset Prices. Mathematical Finance, 19(3), 379-401.
2. Merton, R. C. (1976). Option Pricing When Underlying Stock Returns Are Discontinuous. Journal of Financial Economics, 3(1-2), 125-144.
3. Black, F., & Perold, A. F. (1992). Theory of Constant Proportion Portfolio Insurance. Journal of Economic Dynamics and Control, 16(3-4), 403-426.
4. Kaminski, K. M., & Lo, A. W. (2014). When Do Stop-Loss Rules Stop Losses? Journal of Financial Markets, 18, 234-254.
5. Credit Suisse (2018). Credit Suisse AG Announces Event Acceleration of its XIV ETNs. Press release, 6 February 2018.