# Limits, halts and maintenance

**FUT-22 · Equity Index Futures · Core**

**Lesson question:** Why may a desired exit be unavailable?

Original fictional examples; educational writing, not live market data, orders or production approval.

## By the end

- Explain the mechanism in the lesson question.
- Reproduce the worked comparison and recognize its failure case.

**Prerequisites:** FUT-01

A price limit, a halt and a maintenance interval are different mechanisms. Some constrain prices, some pause activity, and none promises a counterparty at your desired exit. An old displayed quote can remain visible while comparable execution is unavailable.

Exact rules belong to the actual exchange product and broker calendar.

## Understand the mechanism

A stop is an instruction, not a guaranteed price. Gaps and one-sided liquidity can move the next execution far beyond the planned trigger. A theoretical continuous hedge assumes conditions that real trading can violate.

Rules may change, so this lesson does not prescribe universal limit percentages or session clocks.

## Walk through the process

Include an unavailable-exit branch in stress planning. Ask how the position and cash account behave if the next fill is much worse. Confirm the current product rules before relevant events.

Smaller intended risk based on a stop must not be confused with a contractual payoff cap.

## Operational boundary

All figures are fictional teaching inputs, not current quotes or margin schedules. Product rules, broker requirements and usable liquidity remain separate from the model example. A planned exit and an algebraic hedge are not execution guarantees.

## A worked example

A fictional long plans to leave after ten adverse points, equivalent to 500 at a 50 multiplier. A discontinuous move leaves the next available trade twenty-five points lower, or 1,250 adverse before costs.

This is a gap stress example, not a specific exchange-limit report. The graph compares planned and stressed loss distances.

## Graph: Limits, halts and maintenance—worked comparison

**Horizontal:** Adverse exit distance (points)  
**Vertical:** Loss magnitude (USD)

Fictional data from the written example. The chart organizes the comparison; its shape is not a forecast.

Complete numerical data are embedded in `scripts/equity-futures/FUT-22.js` and displayed as an accessible table in the HTML lesson.

## What would invalidate the reading?

Calling a stop a guarantee or treating a limit boundary as guaranteed liquidity understates operational risk.

## Check your understanding

### Can a stop ensure the intended cash loss through a gap?

**Answer:** No.

**Why:** The next executable price can be worse or temporarily absent.

### What is the critical failure to avoid?

**Answer:** Calling a stop a guarantee or treating a limit boundary as guaranteed liquidity understates operational risk.

**Why:** Explain this risk before treating the example as a decision rule. A correct calculation does not guarantee a favorable market outcome. **Critical risk check.**

## Takeaway

Return to the question: Why may a desired exit be unavailable? State the observed facts, the assumptions and the failure condition separately.

## References and provenance

The cited references support definitions and conventions. The teaching prose, tickets and numerical scenarios are original; they are not attributed as historical market observations.

- [CME Introduction to Futures](https://www.cmegroup.com/education/courses/introduction-to-futures)

- [CME Micro E-mini overview](https://www.cmegroup.com/education/courses/micro-e-mini-futures/micro-e-mini-futures-products-overview)