The Kalshi referral code ACTION gives new traders a trade $25, get up to $500 bonus, and Sunday Night Baseball is a prime spot to spend it. Seattle hosts Houston at 7:20 p.m. ET on NBC, and our lean is the Mariners, with a pitching edge that has quietly tilted their way: Bryan Woo (4.15 ERA) faces a Hunter Brown who owns a solid 3.68 season mark but a shaky 4.91 ERA this month.
Enter the Kalshi referral code ACTION at signup and one $25 trade unlocks the reward. Some readers use this as the Kalshi promo code, but both choices point to the same offer. On Kalshi you buy a side as a contract on the prediction markets that settles for cash if it hits, so it is a clean way to back a value play on the MLB nightcap, featuring Mariners vs. Astros.
Mariners vs. Astros Preview and Pick
This AL West rivalry runs through the mound. Woo has been steady for Seattle, while Brown, for all his talent, has scuffled in August and carries a 4.91 ERA over the month. At home against a slumping arm, the Mariners are a live side rather than an underdog you have to talk yourself into. Here are the Kalshi MLB odds for this matchup.
| Market | Contract Price (estimate) | Implied Probability |
|---|---|---|
| Mariners to win | ~52¢ | ~52% |
| Astros to win | ~50¢ | ~50% |
| Over (run total) | ~50¢ | ~50% |
| Under (run total) | ~50¢ | ~50% |
Pick: Mariners to win. Seattle has the ballpark, the crowd, and the steadier starter Sunday night, and Brown's August numbers give Houston a real question mark on the bump. Once the market posts, a $25 first trade at a 52-cent Mariners contract would buy about 48 shares, worth roughly $48 if Seattle closes it out, with the random bonus stacking on top.
Click the module below to register with the Kalshi referral code ACTION to claim your bonus for Mariners vs. Astros:
Kalshi Referral Code ACTION Bonus Chart for Mariners vs. Astros
| Feature | Details |
|---|---|
| Game | Mariners vs. Astros, Sunday, 7:20 p.m. ET on NBC |
| New Sign-Up Offer | Trade $25, get up to $500 |
| Referral Code | ACTION |
| Platform | Kalshi (CFTC-regulated event exchange) |
| Minimum Trade | $25 |
| Reward | Random bonus up to $500, awarded after your $25 first trade |
| Minimum Age | 18+ |
| Eligible States | AK, AL, AR, CA, CO, CT, DC, DE, FL, GA, HI, IA, ID, IN, KS, KY, LA, ME, MN, MO, MS, NC, ND, NE, NH, NJ, NM, NY, OK, OR, PA, RI, SC, SD, TN, TX, UT, VA, VT, WI, WV, WY (42 total) |
How to Register With the Kalshi Referral Code ACTION
- Click the Kalshi referral code ACTION to open the sign-up page.
- Create your account and enter code ACTION when prompted.
- Confirm you are 18 or older and located in an eligible state.
- Fund your account and place a first trade of at least $25.
- Place the $25 trade and a random bonus, worth up to $500, posts to your account.
The Polymarket Route: $20 Trading Bonus
Don't want to stake $25 to start? Take a look at Polymarket. It lists the same Mariners vs. Astros contracts and sits among the best prediction market apps in the space. The offer asks for a lot less up front, just a $10 deposit for a $20 trading bonus.
Claim your offer with Polymarket promo code ACTION and trade on Seattle now. If a set price from a sportsbook more your speed, our sports betting hub and MLB betting promos page have the rest of the ways to get in on the action.
Trade the Mariners and Let the Bonus Ride
Sold on Seattle? Sign up with Kalshi and make your trade on the Mariners. Create your account with Kalshi referral code ACTION, put your $25 opening trade on the Mariners, and find out what the random bonus is once the trade clears.
Terms and Conditions
Certain limitations apply. The offer is available to new users only, subject to the terms and conditions at kalshi.com/tc/500. 18+ only. Restrictions and eligibility requirements apply. Event contract trading involves significant risk and is not appropriate for everyone. Please carefully consider if it is appropriate for you in light of your personal financial circumstances. Kalshi products are not available in all jurisdictions. See kalshi.com/regulatory for more information. Not available in AZ, IL, MA, MD, MI, MT, NV, OH, and WA.
