After a ball has been played, a retirement resolves Yes for the player the tour records as the winner. Matches that never start settle at a fair price on ATP, WTA and Challenger, and at $0.50 on ITF. Suspended or postponed matches stay open and close after the rescheduled match finishes, within two weeks.
Nothing here is advice. Rules are set per market and can change. The market's own rules text wins over this post.
How does Kalshi handle tennis retirements?
The Kalshi tennis retirement rules start with the winner and whether play began. The ATP example's primary rule says:
If Lorenzo Musetti wins the Fritz vs Musetti professional tennis match in the 2026 ATP Stockholm Semifinal after a ball has been played, then the market resolves to Yes.
KXATPMATCH, retrieved 2026-11-13.
The ATP, WTA and Challenger text has no separate retirement clause. After play starts, the player the tour records as the winner resolves Yes under that opening condition. Don't substitute an unfinished score for the recorded winner.
Our guide to what retirement means in tennis explains the sporting result behind this settlement question.
What are Kalshi's tennis walkover and withdrawal rules?
Before play, the decisive fact is that the match never started. The ATP secondary text says:
If the match does not occur (signaled by a ball being played) due to a player injury, walkover, forfeiture, or any other cancellation (all before the match starts), the market will resolve to a fair price in accordance with the rules.
KXATPMATCH, retrieved 2026-11-13.
The same wording was recorded for KXWTAMATCH and KXATPCHALLENGERMATCH. It gives no numeric fair price. You can't infer an amount from the phrase alone.
For a withdrawal, establish whether a ball was played before choosing the settlement branch. The word withdrawal without that timing leaves the distinction unresolved. ITF's pre-start amount is explicit, as the table shows.
| Scenario | ATP, WTA and Challenger | ITF |
|---|---|---|
| Retirement after play starts | Recorded winner resolves Yes | Recorded winner resolves Yes. Withdrawing or forfeiting player resolves No |
| Walkover, injury or withdrawal that prevents the start | Fair price under the rules, amount unspecified | $0.50 |
| Other cancellation before play starts | Fair price under the rules, amount unspecified | $0.50 |
| Suspended, postponed or delayed | Open until the rescheduled match finishes, within two weeks | Open until the rescheduled match finishes, within two weeks |
If you also use Polymarket, our comparison of tennis retirement and walkover settlement rules covers the venues separately.
What happens when a Kalshi tennis match is suspended?
The postponed or delayed clause covers a suspended match:
If this match is postponed or delayed, the market will remain open and close after the rescheduled match has finished (within two weeks).
KXATPMATCH, retrieved 2026-11-13.
A suspension belongs under this clause, with the market open until the rescheduled match finishes within two weeks. The quoted wording doesn't specify what happens after that limit.
We explain what a suspended tennis status means separately. In your match display, keep a pause distinct from a final outcome. An Interrupted label alone doesn't establish a retirement.
What if a Kalshi tennis match is canceled?
The pre-start cancellation language is explicit:
If the match does not occur (signaled by a ball being played) due to a player injury, walkover, forfeiture, or any other cancellation (all before the match starts), the market will resolve to a fair price in accordance with the rules.
KXATPMATCH, retrieved 2026-11-13.
That clause applies when the match never begins. A Cancelled label in live data still needs the timing context. Check whether play started before treating it as a pre-start cancellation. Don't extend the quoted clause to an abandoned match after play began.
How do Kalshi's ITF tennis rules differ?
ITF states a pre-start amount and adds a clause for withdrawal or forfeiture after play begins:
If the match does not occur (signaled by a ball being played) due to a player injury, walkover, forfeiture, or any other cancellation (all before the match starts), all markets will resolve to $0.50.
If a player withdraws or forfeits after a match has started, that player will resolve to No.
KXITFMATCH, retrieved 2026-11-13.
The amount belongs to ITF's pre-start clause. It doesn't supply the missing fair-price number for ATP, WTA or Challenger. The post-start sentence names the withdrawing or forfeiting player's contract and resolves it to No.
How can you read the rules from Kalshi's API?
The public endpoint requires no key for reads. Each market object carries rules_primary and rules_secondary. This example requests open ITF markets and prints both fields without shortening the text.
import requests
response = requests.get(
"https://api.elections.kalshi.com/trade-api/v2/markets",
params={"series_ticker": "KXITFMATCH", "status": "open"},
)
response.raise_for_status()
for market in response.json()["markets"]:
print(market["rules_primary"])
print(market["rules_secondary"])
Read the text for the actual market you're inspecting. For automation, our Kalshi tennis trading bot guide provides the broader development context.
Which live match fields identify the scenario?
We cover ATP, WTA, Challenger and ITF. In Live Tennis API match data, outcome is null until settled. Its closed vocabulary is completed, retired, walkover, default, abandoned and unresolved.
The event_status field passes through labels such as Finished, Retired, Cancelled, Walk Over, Postponed and Interrupted. Preserve that label beside the outcome so you can inspect what the feed reported.
On completed matches only, withdrew identifies which player retired or conceded the walkover, using 1 or 2. It isn't a live injury indicator.
Our method for connecting Kalshi markets to live tennis scores explains the matching workflow. You can get a free API key for live and upcoming match statuses. The free tier returns status, event_status and outcome for those matches. Completed results are on Basic and up.
How this was measured
We measured completed singles matches recorded by Live Tennis API from 1 January to 29 October 2026. The completed count is the denominator for each tour's retired_pct and walkover_pct.
| Tour | Completed count | Retired | Walkover |
|---|---|---|---|
| ATP | 4,005 | 1.85% | 0.3% |
| WTA | 3,892 | 2.44% | 0.31% |
| Challenger men | 10,476 | 2.97% | 0.2% |
| Challenger women | 1,968 | 2.44% | 0.46% |
| ITF men | 17,830 | 3.81% | 0.53% |
| ITF women | 17,243 | 3.21% | 0.67% |
These are shares of completed matches per tour in our records, with retirement and walkover shown separately. They describe recorded outcomes, not the probability that your next match ends that way.
An interruption is a recorded Interrupted status. Its measured pause lasts until the next status change we recorded for that match. That observation doesn't measure a market's settlement time.
Frequently asked questions
Does Kalshi void tennis retirements?
The rule resolves Yes for the recorded winner once a ball has been played. ATP, WTA and Challenger don't add a separate retirement clause in the text reviewed here. ITF also explicitly resolves the withdrawing or forfeiting player's contract to No after the match starts.
What are Kalshi's tennis injury rules?
The timing of the injury matters to the scenario. If it prevents the match from starting, ATP, WTA and Challenger use a fair price under the rules. ITF uses $0.50. If play began and a retirement follows, read the recorded winner against the post-start condition.
Can the same withdrawal label mean different settlements?
Yes. A withdrawal before play belongs to the never-started case when it prevents the match from occurring. ITF explicitly resolves the withdrawing player's contract to No after play starts. For ATP, WTA and Challenger, the recorded winner resolves Yes once a ball has been played.