Tales from Prediction Markets
Prediction markets are fun, at least if you're making money. I've only been into them for a few months, but have already collected a bunch of interesting tales. Note: I may have been involved with some of these, but I'm telling these tales from a third person perspective. One general point: all of these took place on Polymarket, a crypto prediction market. You can track which accounts place each bet, and so you can see their history of bets, but you can't tie it to an actual person unless they've chosen to identify themselves. You can look at the bet history at Polymarketwhales.info, although there's a ton of bets so it's easier if you know what you're looking for. The Tesla market. Polymarket had a market on whether Tesla would announce a Bitcoin purchase by Mar 1, 2021. On January 27, an unknown user bet $60k on Yes. This was their only trade on the site, before or after. They won $180k, or 120k in profit. Odds are pretty good it was an insider. Is this insider trading? I asked Matt Levine but he didn't respond. Anyway, there’s another user that lost $242k betting that Tesla would not announce a Bitcoin purchase. This user is affectionately called the "Tesla whale” on the Polymarket discord. They're also notable for losing $92k on the super bowl the day before Tesla made the announcement, and they get honorable mention for having lost the most money on the 100 million vaccine market: see below. As of this writing, the Tesla whale is down nearly $500k. Watch out for slippage: there was a market on whether Joe Biden would still be president as of Mar 1, 2021. Someone owned around 200k shares of Yes. The market price was very close to $1 each on the morning of Mar 1st, and they apparently decided to sell all their shares instead of waiting for it to resolve; however, there wasn't enough liquidity to sell them all at market price, and they ignored the warning about the slippage the order would encur. Their order ended up executing at an average price of 2 cents, an






The theoretical maximum per flip is doubling your money (if you had a way to just bet on fair coin flips)
You shouldn't settle for 4%. You should be able to get to at least within 10% of optimal, certainly at low bet sizes.
Find an asset that is likely to either double or go to 0. For small amounts you can just pick sports games, learn which side will win then bet on kalshi or polymarket which won't ban for winning every time. Plenty of 50c priced assets. That gets you to 7 figure size
Then you go to option spreads that expire soon at the money, although if you need to source a... (read more)