Cboe began listing binary options on the Mini-Russell 2000 Index (MRUT) today, October 26, 2026, trading under the root symbol MRTBW. These contracts pay a fixed $100 if the index settles at or above the strike at expiration, and $0 if it doesn’t, a flat yes/no payout that works nothing like a standard option.
- Cboe’s new MRUT binary options (root symbol MRTBW) went live for trading October 26, 2026, settling P.M. and cash-settled.
- Payout is fixed: $100 per contract if the Mini-Russell 2000 Index settles at or above the strike, $0 if it doesn’t. There’s no partial payout.
- Contracts trade in penny increments from $0.01 to $1.03, with a contract multiplier of 100, so maximum risk and reward are known before you place the trade.
- At launch, Cboe lists same-day and next-day expirations only, with a new expiration added each trading day.
- This is a different underlying from Cboe’s existing binary-options lineup (S&P 500, Cboe Predicts KPI contracts); it’s the first binary product tied to the Russell 2000’s small-cap universe.
What a MRUT binary option actually is
A standard option’s payout scales with how far the underlying moves past the strike. A $50-strike call on a stock trading at $60 is worth at least $10; at $70, it’s worth at least $20. The payout is a range, not a fixed number.
A binary option strips that out. Per Cboe’s own contract specifications, MRUT Index Binary options (MRTBW) pay exactly $100 per contract if the Mini-Russell 2000 Index’s settlement value is at or above the strike price at expiration, and exactly $0 if it isn’t. There’s no in-between. You’re not buying exposure to how far the index moves, you’re buying exposure to whether it clears one specific line.
The contracts are P.M.-settled and cash-settled, residing exclusively on Cboe’s Matching Unit 31, and trade during Regular Trading Hours, 9:30 a.m. to 4:15 p.m. ET. At launch, Cboe is listing only short-dated contracts: one expiring at the end of the same trading day and one expiring at the end of the next trading day, with a new expiration added every trading day going forward.
Why the Russell 2000, and why “mini”
MRUT is Cboe’s mini version of the Russell 2000 Index, the standard benchmark for U.S. small-cap stocks. “Mini” means the index value, and therefore the options on it, trades at roughly one-tenth the notional size of a full-size Russell 2000 contract, the same role XSP (Mini-SPX) plays relative to full SPX. That smaller notional is what makes MRUT accessible to retail accounts that would find a full-size Russell 2000 options position too large to size reasonably.
Extending binary contracts to MRUT means Cboe now has small-cap exposure inside its binary-options lineup for the first time. Previous binary products have focused on broad large-cap benchmarks: Cboe’s existing S&P 500 binary options (XSPBW/XSPBX, under the Cboe Predicts umbrella) track the S&P 500, and the separately-approved Cboe Predicts earnings KPI contracts track company-specific metrics at 23 individual large-cap names. MRUT is a distinct underlying from both, giving traders who want a small-cap view, rather than a large-cap or single-stock view, a binary structure to express it with.
The pricing structure, in plain numbers
MRTBW contracts trade in penny increments between $0.01 and $1.03, with a contract multiplier of 100. That means:
- The most you can pay for a single contract is $103 (a $1.03 price times the $100 multiplier), and the most you can receive back is $100.
- The least you can pay is $1 (a $0.01 price times the multiplier), with the same $0 or $100 outcome.
- Your maximum loss and maximum gain are both fixed and known the moment you enter the trade. There’s no assignment risk, no early-exercise consideration, and no need to manage a position as the underlying moves, you either collect $100 at settlement or you don’t.
That bounded, binary structure is the entire appeal and the entire limitation at once. You can’t let a binary option “run” the way you can a long call; a correct 2% move and a correct 20% move pay the exact same $100 if both clear the strike.
| Feature | MRUT binary option (MRTBW) | Standard MRUT option |
|---|---|---|
| Payout at expiration | Fixed $100 or $0 | Variable, scales with distance past strike |
| Max loss per contract | $103 (at the $1.03 price cap) | Premium paid (variable) |
| Price increments | $0.01 to $1.03 | Standard option tick sizes |
| Settlement | Cash, P.M.-settled | Cash, standard index-option settlement |
| Assignment risk | None (binary, cash-settled) | None for cash-settled index options |
| Available expirations at launch | Same-day and next-day only | Standard monthly/weekly cycle |
A hypothetical example
Say a trader believes the Mini-Russell 2000 will hold above a specific level through the end of the trading day. This is illustrative only, not a recommendation to take this or any position:
If MRUT is trading near a round level and the trader buys a same-day MRTBW contract at a strike at that level for $0.45 ($45 per contract after the multiplier), two outcomes exist at expiration. If MRUT settles at or above the strike, the contract pays $100, a $55 gain. If it settles below the strike, even by a fraction of a point, the contract pays $0, and the full $45 is lost. There’s no partial credit for being close.
Access: check your broker before assuming it’s available
Cboe’s existing binary-options products, including the S&P 500 binary contracts under Cboe Predicts, have generally listed first and most broadly on Interactive Brokers among major retail brokers, with other platforms adding support over time. Interactive Brokers has historically been the fastest major retail broker to light up new Cboe binary products.
That said, MRTBW is a brand-new listing as of today, and broker-level rollout for a newly listed product can lag the exchange’s own launch by days or weeks even at brokers that already support Cboe’s other binary contracts. Don’t assume MRTBW is tradable just because your broker supports XSPBW or the KPI binary contracts; check your broker’s platform or options chain directly before planning around it.
Bottom Line
MRUT binary options give small-cap-focused traders a fixed-payout, defined-risk way to take a short-term view on the Russell 2000, with maximum gain and loss known upfront. They’re new as of today, thinly supported across brokers at launch, and limited to same-day and next-day expirations for now, so treat early days as a liquidity-and-access learning period, not a signal the product is fully built out.
Frequently Asked Questions
Q: What does MRTBW stand for?
A: It’s the root symbol Cboe assigned to the new MRUT Index Binary options, residing exclusively on Cboe’s Matching Unit 31.
Q: How is a MRUT binary option different from a regular MRUT option?
A: A regular MRUT option’s payout scales with how far the index moves past the strike. A MRUT binary option pays a flat $100 if the index settles at or above the strike, and $0 otherwise, regardless of how far past (or short of) the strike it settles.
Q: What expirations are available at launch?
A: Same-day (0DTE) and next-day expirations only. Cboe adds a new expiration each trading day, so the available dates roll forward daily.
Q: Can I trade MRUT binary options at any broker?
A: Not necessarily. Cboe’s existing binary products have rolled out broker-by-broker rather than appearing everywhere at once, and MRTBW is brand new today. Check your broker’s options chain directly rather than assuming support.
Q: Is this the same as the Cboe Predicts KPI binary options on company earnings?
A: No. The KPI contracts (launched separately, with Robinhood as the first retail broker) track company-specific metrics like revenue or EPS for 23 individual large-cap names. MRTBW tracks the Mini-Russell 2000 Index, a small-cap benchmark, an entirely different underlying and product line.
For a deeper look at how Cboe’s binary-option structure works mechanically, including settlement and the fixed-payout logic, see our S&P 500 binary options explainer.