From Misinformation Underload, April 3:
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, and someone else scooped up those cheap shares a minute later, spending $1k to make $155k; talk about being in the right place at the right time! The initial user ended up with a total loss of $156k on this market. However, even taking that into account, as of this writing they're still up $175k, so don't feel too bad for them. (Note: it's possible they were trying to sell No shares to make a few cents and accidentally clicked on the sell Yes side; without confirmation from the user we can't know what they were intending. Regardless, if you've got hundreds of thousands of dollars at stake, double check before pressing buttons. This isn't the only fat finger that's happened, but it's the biggest.) Polymarket has since added a larger warning in red for trades that move the market more than a few cents.
Hashmasks. There was a market on whether the Hashmasks volume ranking on Opensea would be #1 as of Feb 28, 2021. Someone accumulated over 200k Yes shares, then took out a “flash loan” and purchased a Hashmasks from themselves for 130k ETH (worth over $100 million at the time). Unfortunately for them, Opensea doesn't count sales done directly through their smart contract, only one initiated through their website. The market resolved No.
CO2: Polymarket had a market on whether the level of CO2 reported by the Mauna Lua observatory would be over a specific value on a specific day. The number gets reported on the main page once a day, but someone found a page with the hourly data and figured out how to average together the data points to predict the daily number. They made around $10k on the first market and around $30k on the second market. After that, Polymarket stopped making new CO2 markets.
Vaccines: There was a market on whether there would be 100M 1st doses of covid vaccines reported by the CDC by 12PM EST on April 1st, 2021....
....MUCH MORE
