A full MLB slate hits the board Tuesday, and the night's headliner sends the Seattle Mariners into Yankee Stadium at 7:05 p.m. ET on TBS. MLB prediction market apps put a price on that game the moment first pitch approaches, and those prices keep moving until the final out.
Six platforms lead the category right now: Polymarket, FanDuel Predicts, Kalshi, Novig, DraftKings Predictions, and ProphetX. Each one lists event contracts on Mariners vs. Yankees, the rest of the Tuesday schedule, and season-long markets like MLB MVP.
New traders stack MLB prediction market promos across all six, and the offers below range from a $20 trading bonus up to $500 in bonus credit. Claim them in the table, then read the platform breakdowns to figure out which app fits how you trade.
| MLB Prediction Markets | MLB Prediction Market Apps | Sign-Up Link |
|---|---|---|
| Polymarket | Deposit $10, Get $20 Trading Bonus | ACTION |
| FanDuel Predicts | Sign Up & Unlock Your Offer | Click Here |
| Kalshi | Trade $25, Get Up to $500 Bonus | ACTION |
| Novig | Spend $25, Get $50 in Novig Coins | ACTION |
| DraftKings Predictions | Trade $5, Get $150 in Predictions Dollars | Click Here |
| ProphetX | Trade $10, Get $20 Bonus | TANBONUS |
Best MLB Prediction Market Apps for Mariners vs. Yankees Tonight
All six exchanges below list contracts on the same MLB games, so the differences come down to fees, state access, market depth, and how the app handles in-game trading. Here is what each of the best prediction market apps does well, plus the promo code that unlocks the current welcome offer.
Stack the MLB prediction market promos in whatever order suits your bankroll. Nothing stops you from opening two or three accounts and comparing prices on the same Mariners contract.
1. Polymarket
Polymarket stands as the largest prediction market exchange by trading volume, and its sports board expanded quickly after the platform returned to U.S. traders under CFTC oversight in late 2025. Moneyline, run total, and player contracts on Mariners vs. Yankees all trade there through the final inning, and prices react as soon as lineups post.
The Polymarket promo code ACTION turns a $10 deposit into a $20 trading bonus once you meet the offer terms. Polymarket also supports combo trades of up to 32 legs, which lets you bundle the Yankees side with a Bryan Woo strikeout market inside one position.
| Polymarket Promo Code | Polymarket Referral Bonus | Polymarket States Available |
|---|---|---|
| Polymarket Promo Code ACTION | Deposit $10, Get $20 in Bonus Funds | AL, AK, AR, CA, CO, CT, DE, FL, GA, HI, ID, IN, IA, KS, KY, LA, ME, MN, MS, MO, NE, NH, NM, NJ, NY, NC, ND, OK, OR, PA, RI, SC, SD, TN, TX, UT, VT, VA, WA, WV, WI, WY, DC |
2. FanDuel Predicts
FanDuel carried its sportsbook layout straight into event contracts, so the app reads instantly if you already hold a FanDuel account. The MLB board covers the headline markets rather than every niche prop, which suits traders who want one clean position on tonight's game.
The FanDuel Predicts welcome offer unlocks at sign-up, and the state footprint currently covers 18 states as the rollout continues. Among MLB prediction market apps, this one asks the least of a first-time trader in terms of learning curve.
| FanDuel Predicts Promo Code | FanDuel Predicts Sign-Up Bonus | FanDuel Predicts States Available |
|---|---|---|
| FanDuel Predicts Promo Code (Click Here) | Sign Up & Unlock Your Offer | AK, AL, CA, DE, FL, GA, HI, ID, MN, ND, NE, NM, OK, RI, SC, SD, TX, UT |
3. Kalshi
Kalshi runs as a CFTC-regulated Designated Contract Market with Kalshi Klear registered as its clearing organization, which gives it the deepest regulatory paperwork of the group. The app pairs a same-game parlay builder with markets on MLB, politics, economics, and weather.
The Kalshi promo code ACTION rewards a $25 trade with up to $500 in bonus credit, the largest headline number in this roundup. Robinhood's prediction hub routes through Kalshi's exchange, so the pricing you see on Mariners vs. Yankees carries over between the two.
| Kalshi Promo Code | Kalshi Sign-Up Bonus | Kalshi States Available |
|---|---|---|
| Kalshi Promo Code ACTION | Trade $25, Get Up to $500 Bonus | AL, AK, AR, CA, CO, CT, DE, FL, GA, HI, ID, IN, IA, KS, KY, LA, ME, MN, MS, MO, NE, NH, NM, NJ, NY, NC, ND, OK, OR, PA, RI, SC, SD, TN, TX, UT, VT, VA, WV, WI, WY, DC |
4. Novig
Novig built its exchange sports-first from the ground up, and the company secured CFTC approval in June 2026. The zero-commission structure appeals to anyone who trades in and out of a position multiple times across nine innings.
The Novig promo code ACTION converts a $25 spend into $50 in Novig Coins. Access covers 29 states plus Washington, D.C., with the regulated exchange expanding through the back half of the MLB season.
| Novig Promo Code | Novig Sign-Up Bonus | Novig States Available |
|---|---|---|
| Novig Promo Code ACTION | Spend $25, Get $50 in Novig Coins | AK, AR, FL, GA, HI, IL, IN, IA, KS, KY, ME, MA, MN, MO, NE, NH, NC, ND, OH, OK, OR, SC, SD, TX, VT, VA, DC, WI, WY |
5. DraftKings Predictions
DraftKings Predictions operates as a CFTC-registered Introducing Broker and NFA member, and it claims the widest state map of the six platforms here at 47 states. If your state sits outside the Kalshi or Polymarket footprint, start here.
A $5 first-time trade unlocks $150 in Predictions Dollars, which makes this the lowest entry point among current MLB prediction market promos. The interface mirrors the DraftKings app, so contract prices display in a format sportsbook users already read fluently.
| DraftKings Predictions Promo Code | DraftKings Predictions Sign-Up Bonus | DraftKings Predictions States Available |
|---|---|---|
| DraftKings Predictions Promo Code (Click Here) | Trade $5, Get $150 in Predictions Dollars | AL, AK, AZ, AR, CA, CO, CT, DE, FL, GA, HI, ID, IL, IN, IA, KS, KY, LA, MD, MA, MI, MN, MS, MO, MT, NE, NV, NJ, NM, NY, NC, ND, OH, OK, OR, PA, RI, SC, SD, TN, TX, UT, VT, VA, WA, WV, WI, WY |
6. ProphetX
ProphetX earned CFTC approval in June 2026 and now operates in 49 states, the broadest reach of any sports-native exchange. The app charges 0% on profitable parlays and prints bet slips in American odds, which shortens the jump from a sportsbook to an exchange.
The ProphetX promo code TANBONUS pays a $20 bonus on a $10 trade. Peer-to-peer pricing means you sometimes get a better number on the Mariners than the posted MLB odds elsewhere on the market.
| ProphetX Promo Code | ProphetX Welcome Offer | ProphetX States Available |
|---|---|---|
| ProphetX Promo Code TANBONUS | Trade $10, Get $20 Bonus | AL, AK, AZ, AR, CA, CO, CT, DE, FL, GA, HI, ID, IL, IN, IA, KS, KY, LA, ME, MD, MA, MI, MN, MS, MO, MT, NE, NV, NH, NJ, NM, NY, NC, ND, OH, OK, OR, PA, RI, SC, SD, TN, TX, UT, VT, VA, WA, WV, WI, WY |
How to Sign Up and Claim the Best Prediction Market Promos
The process takes about five minutes on any of these platforms:
- Tap a sign-up link in the tables above to lock the offer to your account.
- Enter the promo code listed for that platform during registration.
- Verify your identity with your name, address, date of birth, and the last four digits of your SSN.
- Fund the account with a debit card, bank transfer, or, on Polymarket, USDC.
- Place the qualifying trade to release the bonus, then head to the MLB tab.
One point worth understanding: event contracts fall under federal CFTC regulation rather than the state licensing framework that governs sportsbooks by state. That distinction explains why these apps reach 40-plus states while the answer to where is sports betting legal still stops around 39 markets. State regulators continue to challenge that federal footing in court, so availability shifts.
Mariners vs. Yankees MLB Odds and Contracts to Watch
New York enters at 66-52 and sits comfortably in the AL East picture. Seattle arrives at 56-63, and the offense ranks last in baseball at 3.9 runs per game despite a team ERA of 3.78 that ranks eighth.
The pitching matchup pairs Bryan Woo (8-8, 4.31 ERA, 127 strikeouts) against left-hander Ryan Weathers (5-7, 3.79 ERA, 132 strikeouts). Prediction markets price the Yankees near 54% with the Mariners at 46% and the total at 7.5.
Season-long boards on MLB prediction market apps deserve a look too. Yordan Alvarez holds a commanding grip on the AL MVP market after a rib injury knocked Aaron Judge out of contention, and Pete Crow-Armstrong recently overtook Shohei Ohtani as the NL favorite. Those MLB MVP contracts trade on every platform above.
