Make it optional. On subjective markets I can select an option to ban myself from trading, which I can't undo later. On more objective markets there's no reason I shouldn't be able to trade.

@IsaacKing This doesn't solve the problem of people creating subjective markets and not selecting that option. People already have the ability to promise "I won't trade in this market because the resolution is subjective", and these promises are already credible despite not being enforced by the interface. So just creating the option doesn't add much unless it's at least a strong default that causes people to make these promises where they wouldn't otherwise have made them.

@StevenK It adds option to enforce it, which might be crucial difference for the people who mind people trading in their own markets. (Or it might even change the probabilities, as now people factor the misresolution in)

A happy medium could be a flag "Creator can trade" settable at market creation. If the flag is visible to anyone, betters can rest assured the creator won't bet on their own market, but also allows self-regulating markets where creators can bet on/againts themselves.

I don't bet on markets I create, and I think an outright ban is certainly not the answer. I don't think anybody has a grand unified theory of the best way to handle prediction markets, and randomly guessing through regulation is a mistake. If people prefer markets where the creator hasn't bet, then those markets will be more successful in the long run. I think there could be adjustments, an indicator that the creator has traded on the market (even if it's subtle and only under the "positions" tab) would probably be beneficial. It could also be a good idea to prevent the creator resolving a market soon after they've bet on it. For example, betting on a market and then resolving a few seconds later is fairly clearly not "prediction".

@Sailfish

If people prefer markets where the creator hasn't bet, then those markets will be more successful in the long run.

I disagree. People bet in markets where it looks to them like they can make a profit. When there's uncertainty about a market being motivatedly resolved, different people will (perhaps without even realizing it) have different beliefs about the motivation, and this will sometimes drive persistent betting and end in drama.

Like a lot of other commenters, I'd prefer something voluntary. I'd actually prefer a note over a toggle because I feel like we're getting to too many of these toggles. Maybe this could be accompanied by a warning when someone is about to trade in their own question, in order to inform new users on why this may not be a good idea.

I think there should be a toggle on all markets (kind of like the non-predictive toggle) that the market creator can switch on to permanently disable their ability to trade on the market, including the ability to sell positions they already own.

I regularly bet on objective markets that I create, and sometimes place bets as insurance on some subjective/personal markets (when I do this, I state it clearly in the description.) I'd be upset if I lost the ability to do that, especially since I'm the only trader on a lot of my Splatoon markets, Pokemon markets, etc.

The more users Manifold has, the less of a problem it becomes where someone can’t bet on a market because it doesn’t yet exist.

For that reason, eventually, YES. For now, NO

Nah:
- often you make a market because you're interested in the topic and want to trade on it
- the review system already deals with major incentive misalignment problems

Some better proposals:
- Make it easy for users to see if the market creator has bet in their own market
- Allow market creators to give away their resolution power to someone else

@DanielFilan I say this as someone who recently got burned by someone resolving their market against me, in a resolution I regard as incorrect, when they had traded in their own market and profited from their own resolution.

@DanielFilan

often you make a market because you're interested in the topic and want to trade on it

If enough people care, someone will make it. I imagine that if users couldn't trade on their own markets, a market creation requests thread would pop up somewhere. Manifold already incentivizes creating a lot of markets, even when they're low quality markets that crowd out high quality markets.

the review system already deals with major incentive misalignment problems

How many users click through to a market creator's reviews before betting? Even a 5% chance of corrupt misresolution can drive a lot of betting and worrying, and won't come to light until ~20 markets have resolved. Your recent experience is an example of the review system not working.

@StevenK I agree that it sucks that you have to click thru to see reviews, and that should be fixed. I'm not particularly worried about too many markets, and think that your other issue can be fixed by my solutions.

@DanielFilan There's a danger of saying "we shouldn't change the bad thing to a good thing, because an even better thing than the good thing is possible", and then keeping the bad thing. I'm not worried about too many markets so much as worried about lower average market quality, with worse markets taking attention and mana away from better markets. (For example, anyone who wants to efficiently bet on Biden becoming president currently has to hunt down something like ten different markets.) I think your solutions would partially work, but not reliably, because many market creators wouldn't opt in, and many traders would continue to trade in bad markets.

I do think that for higher-stakes markets, it is better for the market creator to not be trading, but I think it would be heavy-handed and unfun to disable it for all markets.

Would also wipe out personal goals/commitment markets.

I think a more nuanced approach could be for the market creator to have the option of disabling self-trading on particular markets, and perhaps for that to be indicated somewhere on the market.

I foresee a Manifold where all the most respected big-time market creators are never trading in their own markets.

@Charlie Could also disable profit from one’s own markets or profit from the AMM? Like, maybe you can only make profit from your own market if someone else bets against you?

I think that should be the default for new accounts, which all too often make subjective markets, bet on them, and resolve in their favor. Once your account has existed for a bit, then you should be allowed to check a box at market creation that lets you bet in it and lets other people know you can bet in it. Same thing as the restriction on new accounts and managrams.