MANIFOLD
Insider Coinflip
95
αΉ€1kαΉ€26k
resolved Jan 12
Resolved
NO

I have already tossed a fair (virtual) coin and recorded the result. At market close, it resolves YES if it was heads, NO if it was tails.

I have also selected a timestamp uniformly at random between 1 day from market open, and 6 days from market open (market duration is 7 days).

At the pre-selected timestamp (or near enough if I happen to be asleep or whatever), I will select a holder at random to be the "insider" (see footnote for precise method). I will DM that user the result of the coinflip.

I will not bet in this market. I will not sell info, take bribes, or answer questions about who the "insider" may or may not be, etc. etc.

Precommit hash: cbe2ba0a741d526098e3244a14ec084b9ca3e75b254c76c7450a8808385f1a00

(at market close I will publish a text file with the coin toss result, timestamp, and 128-bit integer n that hashes to this sha256 result)

User selection:
I'll make a list of all holders (both YES and NO), sort them alphabetically (by utf8 codepoints), and select the user at index n modulo the list length.

  • Update 2026-01-04 (PST) (AI summary of creator comment): Bot accounts are not eligible to be selected as the insider and will be excluded from the list during the selection process.

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Hey @retr0id , I don't think you did anything dishonestly but I'm having trouble getting the right hash out of your precommitment. I'm getting

e40a423aa0ce944e9c5f4be73209a5f72b3e601b770bb8d87509e4a0b8b93b03

from two different tools?

@moobunny oops the version I uploaded is missing a line ending (\n)

I've edited it to match now

@retr0id that does it, thanks!

@moobunny ty for checking!

I'm bookmarking this into my archive of things I can point to when people say that prediction markets can be manipulated.

@Quroe What point would you be trying to make?

@SimonWestlake It depends! I think the conversation would open with an explanation of how this market was set up, and I'd ask my conversational counterpart what they think the market chart looked like. We can actually back test whatever hypothesis they have in the moment!

I also think that my observation here is notable.

gg everyone - resolves NO

precommit file + user list used for selection: https://gist.github.com/DavidBuchanan314/20057123524b063920b9db3a124d29e1

btw the intended DM timestamp was 2026-01-07T04:19:55Z but I was asleep then, the actual DM took place at 10:57:44am (with the user selection happening shortly beforehand)

bought αΉ€0 YES

Thanks to everyone who allowed me to more than double what my earnings would have been if I just bet the market down to 1% initially!

@SimonWestlake I fully expected to make less money this way

@SimonWestlake Yes I was quite impressed - the "boring" approach should have allowed you to drain the 1k mana from the AMM liquidity and nothing more

@SimonWestlake This was a lot of fun, well played!

Look at how much profit I made per amount spent!

Does anyone know why manifold glitches like this?

@Velaris This is probably not a glitch: you bought shares cheaply, and sold a large part of them for profit. This means you've spend little on your remaining shares, but have already made a profit.

@FlorisvanDoorn plausible, but I didn't make anywhere near that much profit.

Last chance for free mana!

I've extended the limit orders that sell off my entire valuation. They now expire 2 hours before the market closes.

I am the Insider, and this market will resolve NO. I am doing this in hopes of looking shady enough to scare someone into driving up the percentage so that I can buy more NO shares at a good price.

There is zero chance I would dump so much of my net worth into my faith in my ability to manipulate people. I'm absolutely not lying.

If you trust me, you've got a great opportunity to dump a large amount of mana into a market that will give you a same-day profit on it.

opened a αΉ€240 YES at 4% order

Let's keep this interesting to the end. Selling a small amount at 10% was reasonable enough, but given how much I've put in, I'm not going to sell the rest at more than 5%. Limit orders for my entire stake are up for the next hour.

@moobunny

@moobunny If you read it correctly, it's actually guaranteed profit.

I understand why you wouldn't trust it, of course, but it's an opportunity to sink a lot of mana into a sure-thing quick turnaround. This market will resolve NO.

And if you don't trust me when I say that, why the hell do you have so many NO shares?

@SimonWestlake Because you have far more NO shares than you can reasonably expect to liquidate… unless I buy them all off you.

Though if this has been YES all along you’ve got nerves of steel!

@moobunny It’d have to be someone else anyway, I don’t have nearly enough mana to be buying all that off you.

opened a αΉ€150 YES at 5% order

@moobunny Have you seen my net worth? I can't afford such nerves of steel (plus I just don't have them in general)

@SimonWestlake So you must be really sweating right now!

opened a αΉ€500 NO at 10% order

@moobunny Here’s another chance to sell some at 10%, but after that I’m tapped out.

I'm good. That will not serve my goals of getting people to buy YES or sell NO better than the extended pitch I just posted.

@moobunny it's pretty annoying that you'll get the first 500 NO shares that come from people not trusting me lol

filled a αΉ€500 NO at 7% order

I bought some extra NO shares to compensate

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