MIAX Gets Nod for Tiny Stock Index Options Trading
Published Date: 8/13/2025
Notice
Summary
The Miami International Securities Exchange (MIAX) got the green light to start listing and trading options on tiny, focused stock indexes called micro narrow-based indexes. This change means investors can now trade smaller, more precise index options on MIAX, just like on other big exchanges. The new rules kick in soon and could open up fresh, affordable trading opportunities for folks who want to play in the options market without going big.
Analyzed Economic Effects
5 provisions identified: 4 benefits, 0 costs, 1 mixed.
MIAX Lists Micro Narrow Index Options
MIAX is now approved to list and trade options on micro narrow-based security indexes. This gives investors an additional way to gain or hedge exposure to small, focused indexes and may encourage market makers to provide more liquidity and more competitive quoting on MIAX.
Specific Listing Requirements Set
MIAX will only list micro narrow-based indexes that meet specific standards such as having nine or fewer components or component-weight rules (e.g., a component may exceed 30% or the five highest components may exceed 60%). Components generally must have at least $75,000,000 market capitalization (or $50,000,000 for certain low-weight components) and minimum average daily trading volume tests such as 45,500 shares (with some lower exceptions of 22,750 shares).
Position and Exercise Limits Defined
MIAX adopts position and exercise limits for micro narrow-based index options. Members must follow applicable Cboe position-limit rules where relevant; reduced-value contracts will be aggregated with full-value contracts at a 10:1 ratio (ten reduced-value options equal one full-value contract); exercise limits will match the nearest-expiration position limits.
Surveillance and Oversight Measures
MIAX will apply surveillance procedures to micro narrow-based index options, including real-time price and volume monitoring and post-trade patterns (e.g., spoofing, marking-the-close). MIAX is a member of the Intermarket Surveillance Group and uses information sharing plus a FINRA 17d-2 arrangement to support surveillance and enforcement.
MIAX Will Use Cboe Position-Limit Rules
MIAX will incorporate by reference applicable Cboe rules for position limits on micro narrow-based index options and will provide written notice to Members when Cboe proposes changes to those rules. The Commission granted MIAX an exemption under Section 36 so MIAX need not file separate Section 19(b) rule changes for those incorporated-by-reference Cboe rule changes, subject to MIAX notifying its Members.
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