[bluGill]

In Stocks exchanges and brokers are different things. Exchanges list companies, they are the places where different brokers gather to exchange stocks and agree on prices. Brokers are people/companies who go to the exchange on your behalf (historically someone physically went there, now it is mostly computers)

NYSE and NASDAQ do complete with each other for companies to list on them. (as do other exchanges around the world). When a company is on more than one exchange there are people who make it their job to run "arbitrage" - this is they buy on one and sell on the other anytime the prices are different and this keeps things in check.

It is also valid for betting platform to run arbitrage with their competitors - but various anti-monopoly laws and other such things should(!) get in the way. I don't know what they are doing about this or exactly what the law says. As such I don't know what Betfair is really doing, but I know this is a risk they somehow either take (which if they are national might be low enough), or if they somehow get arbitrage done.

And betting platform is normally both the exchange and the broker. As such they have this risk and need to mitigate it while staying within the law. There are many ways to abuse mitigation that need to be illegal and so it must be hard to mitigate - this doesn't mean impossible.

[kgwgk]

> And betting platform is normally both the exchange and the broker.

Betting exchanges are different from bookmakers.

https://www.wikipedia.org/wiki/Category:Betting_exchanges

Maybe you’re now using “platforms” to refer to everything but the discussion was specific to exchanges as opposed to bookmakers.

[bluGill]

Correct me if I'm wrong, but my understanding is all the online options are platforms - the exchange for their own bookmakers. Vegas does have exchanges, but most online options don't use them.

[kgwgk]

You’re wrong. See link above.

How Kalshi and prediction markets are disrupting sports betting: https://www.espn.com/espn/betting/story/_/id/45377686/kalshi...

[bluGill]

That ESPN link doesn't tell me anything. Wikipedia says Kalshi is trying to become available on other brokers, but also implies that the majority of their "trades" come from their own in house brokers.

As such I still need to stand by what I said: at least for now the online platforms are not exchanges (though some are trying to move that way)

[kgwgk]

> The company says one difference is that users are not going up against the house but instead trading contracts with other users on the opposite side of the proposition.

> "We are simply an exchange. So we sit between people that are buying contracts on a yes and a no side. We don't win by people losing. And we don't lose by people winning. We simply sit in between that transaction."

I don’t know what else would you like to be told. That’s an exchange, with one user taking one side and another taking the other side. No brokers are involved when end-users connect directly to the exchange.

Wikipedia mentions that they would like other platforms to give access to the exhange, and the existence of market makers (one affiliate company, one independent company) that may provide liquidity. But the basic exchange is user-to-user.