Polymarket vs Kalshi Sign-Up Bonuses Compared (2026)

If you're researching prediction-market sign-up bonuses, the comparison you actually want is Polymarket vs Kalshi. Every other platform either doesn't have meaningful liquidity (Manifold, Augur), is region-locked to somewhere you don't live (Smarkets, Betfair Exchange), or doesn't run a public new-user promotion (most CFD platforms with event-style markets). Polymarket and Kalshi are the two that matter, and they're set up almost as mirror images: Polymarket is the global-but-US-blocked option, Kalshi is the US-legal option that's growing fast.

This post is the honest head-to-head on their bonuses, referral programs, and sign-up economics in May 2026. We'll cover what each currently offers in broad strokes, the hidden costs the headline bonus numbers never mention, the US-eligibility question that decides 80% of this for most readers, and the math of when the bonus is worth chasing vs. when it's a distraction.

TL;DR

• If you're in the US: Kalshi is your only legal option of the two. Polymarket geo-blocks US users entirely. The "comparison" is between a real US-legal exchange and one you cannot use; take Kalshi.
• If you're international: Both are legitimate. Polymarket has deeper books and longer history; Kalshi has tighter US-regulatory oversight, which matters more for institutional users than individuals.
• Headline bonuses on both platforms typically fall in the $5-$30 range, contingent on minimum deposit + minimum trading volume. Specific amounts change monthly.
• The bonus difference between the two is usually small. Picking a platform based on the current sign-up offer is the wrong optimization.
• What matters more than the bonus: which platform has deeper liquidity in the markets you actually want to trade, what the after-fee economics look like, and whether you have a calibrated probability source. Without the third, the first two don't matter.

If you came here looking for "USE CODE X FOR $X FREE," see our Polymarket referral codes guide for why that frame is a trap.

The Single Most Important Question First

Are you in the United States?

If yes, this comparison is effectively over before it starts. Polymarket has geo-blocked US users since the CFTC's 2022 enforcement settlement. The website doesn't load for US IPs, the KYC system rejects US-issued ID, and the platform actively works to prevent US accounts from operating through VPNs. Whatever Polymarket's current sign-up bonus is, you cannot legally claim it as a US person.

Kalshi, by contrast, is a CFTC-regulated Designated Contract Market headquartered in New York. It exists specifically to be the US-legal version of what Polymarket is internationally. ACH funding, standard US KYC, 1099 tax reporting at year-end, the whole stack.

For US readers, the rest of this post is mostly informational. Your sign-up path is Kalshi. The Polymarket sections explain what you're not eligible for so you understand the landscape, not so you can chase it.

For international readers, both platforms are real options and the rest of the post is the actual comparison.

What Each Platform's Sign-Up Bonus Typically Looks Like

Promotional offers change frequently on both platforms. We're going to describe the typical structures rather than name specific dollar amounts that will be wrong by the time you read this. Always verify the current offer on the platform directly before depositing.

Kalshi

The standard Kalshi new-user promotion has historically been a deposit-matching credit — sign up, deposit a minimum amount (typically $25-$100), get a percentage match or fixed credit applied to your account after a qualifying period of trading activity. Common structures:

• Welcome credit: Flat dollar amount credited after first deposit + first trade.
• Deposit match: Percentage of first deposit credited up to a cap.
• Trading-volume rebate: Trade a target amount in your first 30 days, receive credit equal to a fraction of your trading volume.

Kalshi also runs a referral program where both the referrer and the referee receive a credit when the referee signs up through a personal referral link and completes a qualifying action. The credits are typically in the $5-$25 range per side.

What stays the same across all these promotions: the credit is not withdrawable cash on day one. It's trading credit you have to use on the platform, sometimes with explicit "wager X to unlock" terms similar to a sportsbook bonus.

Polymarket

The Polymarket new-user offer has historically been smaller in headline dollar value but cleaner in mechanics. Common structures:

• Deposit credit: Sign up via a referral link, deposit USDC, receive a small bonus credited to your account.
• No-deposit credit: Occasionally Polymarket has run promotions giving a few dollars of trading credit just for completing KYC, with no deposit required.
• Event-specific promotions: Around marquee events (Super Bowl, US election, World Cup), Polymarket sometimes runs limited-time bonuses on specific markets.

Polymarket's referral program pays the referrer a percentage share of the referee's future trading fees for some period. The referee typically gets whatever the standard new-user offer is — the referral code doesn't enhance it.

Polymarket's bonuses tend to be smaller than Kalshi's because Polymarket is the larger and longer-established platform; its customer-acquisition cost is lower and it doesn't need to subsidize sign-ups as aggressively.

The Side-by-Side Comparison

Because the bonus dollar amounts move, the more useful comparison is on structural dimensions that don't change month to month.

The headline bonus is one row in this table. Several of the other rows have larger impact on your real economics over a year of trading.

The Costs the Bonus Headline Doesn't Mention

A few things to factor in when evaluating either bonus:

1. Funding Cost

On Polymarket, depositing means moving USDC onto Polygon. If you already hold USDC on Polygon, this is essentially free (a few cents in gas). If you're starting from a US bank, you're looking at: bank → CEX (Coinbase or similar) → buy USDC → withdraw to Polygon. Each step has fees and time. First-time funding can cost $5-$25 in total transaction friction depending on which CEX and which network fees you hit. That's gone before you've placed a trade.

On Kalshi, ACH funding from a US bank is free and arrives within a few business days. There's no friction tax. This is a real advantage for US users that doesn't show up in any bonus comparison.

2. Trading Fees

Polymarket charges 2¢/share taker on most markets. On a $100 trade in a 50¢ market (200 shares), that's $4 in fees if you cross the spread. Maker fees are 0¢, so passive limit orders avoid this — but only if you're willing to wait for fills.

Kalshi's fee structure varies by market and contract type. The headline per-contract fee is often comparable or slightly lower than Polymarket's effective taker, but the total dollar fee per trade depends on the market. On thinly traded sports props, the effective spread cost can be higher than Polymarket.

For a $20 bonus to be net-positive, your first month's fee bleed has to be less than the bonus. On a heavy new-user trading sprint to unlock the bonus, this is closer than people realize.

3. Withdrawal Cost

If you ever want to take money off Polymarket, you're moving USDC back through the same Polygon path you used to fund. Trivial gas, but if you want fiat, you're going through a CEX off-ramp again with its fees and KYC requirements.

Kalshi withdrawals are ACH back to your US bank account. Free but takes 1-3 business days. Slower but cheaper.

4. Tax Friction

Kalshi sends US users 1099 forms for trading activity. Income is reported, you file accordingly. Annoying but clean.

Polymarket sends nothing. As a US person trading via VPN (which, again, we don't recommend), you're on your own to calculate cost basis and report — and the platform's lack of US presence makes obtaining records harder if you ever need them. The bonus is denominated in USDC; the IRS treats this as property, not cash, which complicates the math further.

For US users this asymmetry alone is a significant non-bonus reason to prefer Kalshi.

5. Account Risk

Polymarket has, historically, frozen accounts that it later identified as US-based, with withdrawals processed only after substantial delay (sometimes weeks). The risk of bonus dollars being clawed back along with your initial deposit is non-trivial for US users on the platform.

Kalshi has no equivalent risk for US users since it's the platform they're targeting.

A Realistic Dollar-Value Comparison

Putting concrete numbers to the framework, suppose:

• Kalshi's current new-user offer: $25 trading credit after $50 deposit + $200 trading volume.
• Polymarket's current new-user offer: $10 trading credit after deposit + KYC.

Naive comparison: Kalshi wins by $15.

Accounting for friction:

Kalshi: - Funding cost: $0 (free ACH) - Required trading volume: $200, fees ~$2-4 - Net bonus value: $25 − $3 ≈ $22

Polymarket (assuming you're international and eligible): - Funding cost: $5-15 if you don't already hold USDC on Polygon - Required trading volume: low / none - Net bonus value: $10 − $10 ≈ $0-5 first time; $10 net if you already have USDC

On these typical numbers Kalshi wins on net bonus value for a fresh-from-fiat user. Polymarket wins only if you already have USDC on Polygon and there's no funding friction.

This isn't a fixed answer — the platforms vary the offers — but the framework is what to apply when the numbers in front of you are different.

What Actually Determines Profitability After Sign-Up

Here's the part of the comparison that should drive your decision and that no "best sign-up bonus" article ever covers:

Market depth in the things you actually want to trade

Polymarket has deeper books on virtually everything compared to Kalshi today. NBA in-game moneylines, NHL moneylines, soccer, tennis, esports, the long tail of politics and economics — Polymarket's order books are deeper, spreads are tighter at the inside, and the platform handles size better.

Kalshi's depth is improving fast, particularly in NFL, NBA, MLB, and major tournaments. But on niche markets and props, you'll still hit thin books and wider spreads.

If you're trading $50 per trade, both platforms work. If you're trading $500-$5000 per trade, Polymarket's depth matters more.

Your model's edge

Both platforms are reasonably efficient in the markets that get attention. They have the same vulnerability: niche markets and live-trading windows where the order book moves slower than information arrives. If you have a calibrated probability model, the edge is in the niches, on both platforms.

If you don't have a model, you're trading against the consensus of people who do. The bonus does not save you. Expected return over time is whatever your edge is minus fees minus slippage, where your edge — without a model — is approximately zero.

Calibration drift

Even with a model, calibration drifts. Re-checking your model's predictions against actual closing prices weekly is the difference between catching a degraded model in March and discovering it in April. Most retail traders never do this. The platforms don't help you here — it's on you.

This is the reason ZenHodl exists as a product. We publish calibrated probabilities, live-tested, with CLV reporting per sport so you can see whether the model's actually working. If you'd rather skip the model-building entirely and trade against the API directly, pricing is here.

What US Readers Should Actually Do

1. Sign up at Kalshi. It's the US-legal exchange. Claim whatever the current new-user offer is. Standard ACH funding, no VPN gymnastics.
2. Don't VPN into Polymarket. The legal gray zone isn't worth $5-$20.
3. Get a calibrated probability source. Either build one or subscribe to one. Without this, the bonus is moot.
4. Track CLV from your first trade. This is the only honest measure of whether your trading has edge. See our CLV explainer on the partner site.
5. Wait on Polymarket. A US-legal Polymarket via acquisition is expected in late 2026 or 2027. When it launches, the same model layer you've been using on Kalshi will route to it.

What International Readers Should Actually Do

1. Look at both platforms' current promotional offers directly on the sites. Take the bigger one if there's a meaningful difference; default to Polymarket if they're comparable (deeper books matter more long-term than $10 of bonus).
2. Use any legitimate referral code to claim the bonus (most affiliate codes work the same; pick one from a publisher you'd like to support, or default to no code at all).
3. Don't optimize sign-up around the bonus. Optimize around which platform has the markets you'll actually trade.
4. Avoid the "claim multiple bonuses with multiple accounts" temptation. Both platforms detect duplicate accounts and the term-of-service violation cost (account closure with funds locked) exceeds the bonus value 10-100x.
5. Get a model. Same as above. Edge is what makes any prediction-market account work; bonus is a one-time tip.

Common Questions

Which platform has a bigger sign-up bonus right now? Both vary monthly. Generally Kalshi's headline number is larger because they're newer and acquiring users harder. Always verify current offers on each platform's site.

Can I sign up for both? If you're international and eligible for Polymarket, yes — claim both. They're independent platforms with independent promotions. Just don't use the same identity to create duplicate accounts on either.

Is a Kalshi bonus better than a Polymarket bonus dollar-for-dollar? Mostly, yes, for US users — because Kalshi is the only legal option, the comparison is moot. For international users, Kalshi's headline bonuses are typically larger but come with higher volume requirements; Polymarket's are smaller but unlock with less activity.

Are there other prediction markets with bonuses? Manifold Markets uses play money (Mana), so the "bonus" is non-cash. Smarkets and Betfair are exchanges that occasionally run sign-up promotions but focus on traditional sports betting markets, not event contracts. None compete with Polymarket or Kalshi on bonus dollars for prediction-market-style contracts.

What's the catch with these bonuses? Almost always a minimum trading volume requirement before the credit becomes usable. Sometimes a deposit minimum. Always a non-withdrawable trading-credit format — you can use the bonus to trade, but you can't deposit $50 + $25 bonus and then withdraw $75 the next day.

Do bonuses ever get clawed back? Yes, if the platform detects multi-accounting, identity fraud, or terms-of-service violations. Bonuses for US users on Polymarket (claimed via VPN) have been clawed back when accounts were later identified.

Can I refer a friend on both platforms? Yes, the programs are independent. Earnings on one don't affect the other.

Bottom Line

Polymarket vs Kalshi as a sign-up bonus question is mostly answered by your location. US users go Kalshi. International users can claim either, and the deeper-book question matters more than the marginal bonus dollar.

What ultimately separates a profitable account from an unprofitable one on either platform is a calibrated probability model and an honest tracking discipline, not the welcome bonus. The bonus is a $10-$30 nice-to-have on the way in. The model is the difference between profitability and donating to the order book.

If you're starting from scratch and want to skip the model-building, the ZenHodl API publishes calibrated win probabilities for the sports both Polymarket and Kalshi trade — the same probability layer that powers our internal bots. That's where the conversation about prediction-market profitability actually begins.

Further Reading

• Polymarket Referral Codes & Bonuses: What's Real in May 2026 — the full-stack honest guide to the referral-code category.
• Is Polymarket Legal in the US? The 2026 Answer — the regulatory picture in detail.
• Polymarket vs Kalshi: Sports Prediction 2026 Comparison — the full head-to-head beyond just the bonus question.
• How to Bet on Polymarket: First-Time User Walkthrough — operational guide once you've chosen.
• Kelly Criterion for Prediction Markets — what to do with your bankroll once you have edge.
• ZenHodl pricing — the calibrated probability API that determines whether any of this is profitable.