(Cross-posted from https://news.manifold.markets/p/interview-with-1-leaderboard-bettor)
Some additional context for EAs less familiar with Manifold Markets... We are a prediction market website that are looking to make forecasting go mainstream! Our approach is to gamify prediction markets, prioritise their social features, and lower the entry barrier. We love working with EAs and hope that our markets can empower everyone to make more informed decisions. To that end, we have made it so you can embed our markets on various sites including this one!
We recently hosted Mexifold where we invited our users and EA enthusiasts to come together for 2 weeks! We are also looking forward to meeting everyone at EA Global: Washington DC this September!
We are also looking to match donations to non-profits through our site! We would love to hear from you if you want your organisation to be featured!
Today we want to share an interview we conducted with ranked one leaderboard bettor Joel Becker! Joel rose to prowess and was at the top of the leaderboard only a few weeks after joining Manifold thanks to his market manipulation strategies.

Joel: “The Manifold team were invited to the program I run at FTX. I had heard of Manifold previously through Scott Alexander’s Mantic Monday’s newsletters — more or less as the crazy prediction site that lets you bet on anything — but not yet made the jump. A combination of meeting the team and a sense of competition with my peers lead me to start using the platform.”

See if you can spot Joel and the five Manifold members amongst the other EA Fellows and visitors!
Joel: “In the unusual world in which I find myself, for better or worse, doing well on a prediction markets website is somewhat of a badge of honour. Metaculus is already a well-established website; there’s no chance I can start topping it. Manifold, on the other hand, is a very well executed platform with integrations with the EA forum. Betting on Manifold is the higher-EV route to tongue-in-cheek social prestige. I wish I had more noble motivations but, alas, I think that’s a good chunk of it.”
Interviewer: “I suspect a lot of users coming to our site will be in that category of wanting to outperform their friends. It’s a use case we are planning to start tailoring our website more towards. As part of that we are adding ongoing daily, weekly, and monthly leaderboards!”
Joel: “Oh, that’s terrible! Before there was only one leaderboard and I was winning on it!
“Another important motivation for me using Manifold relates to charitable giving. As an undergraduate, I gave a pretty large fraction of my income to charity, as a graduate student I donated very little, but now being in a proper job I can afford to start donating quite a bit more again.
I think that “trying to learn about the future” is currently a very minor motivator for me. But I can imagine it being a much larger part of the motivation at some later point.”
Within the first week of using the site, Joel was sitting comfortably in the middle of the leaderboard. This was partially thanks to his astute betting, but insider opportunities that presented themselves whilst being with the Manifold team in Nassau helped!
The vector that propelled him to the top of the leaderboard was his profitability on predicting how much money would be donated in June to charity after donating $4,200 last minute! We were curious to learn more about his strategy and how he executed his plan so successfully. One thing to note is that betting was effectively anonymous when this took place, although Joel isn’t convinced that things being public would have changed much.

Interviewer: “Were you always intending to donate in the ballpark of $4000, or did you only donate that much because you wanted to change the answer of the market to $5000-10,000?”
Joel: “Do you remember the total that ended up being donated? It was $5004. So what do you think the answer is (we both had a good laugh at this)! The truth is, I realised that the problem with making it big on Manifold is that there are some markets in which I felt I had an edge in and others that have high enough volume to make a profit. The intersection between these markets is very small… but here it was! This massive, easy-to-manipulate market right on the front page of Manifold, which aligned with my personal goals of wanting to donate more to charity.”
He then proceeded to break down his strategy and what happened, which we will summarise in bullet points alongside some quotes from Joel.
Joel, “And then I realised, do I want to donate the marginal hundreds of dollars to GiveWell? Well, of course I do!”
Joel, “You don’t want to alert people to the manipulation too early. You can see starting from mid May I began pushing down $500-1000. If I pushed it to 1% then people would clearly see what was going on. I wanted them to think it was just stupid pricing, so I push it down reasonably low and slowly bring $1000-5000 up over time.”
Joel, “And then you realise somewhere along that journey, do I want to donate $4000 to GiveWell? Yes! The answer is clearly yes!!! Now there is this ginormous pool of everything less than $5000 to take advantage of.”
Joel, “The thing that seems optimal ex-post was for me to have sold all my shares above $10,000, which I still held a lot of. But I was nervous that some people would put in a couple thousand each at the end and push it above $10,000.”
Joel's total profits on this market were 30,332 Mana (the equivalent of $303 if he were to donate it to charity). He only recuperated a fraction of what he donated, but he achieved his two primary goals of donating to charity and outperforming his friends (and everyone on Manifold for that matter)!
Finally, we wrapped up the interview by asking him what features he would really enjoy using if they were added to Manifold. Here is a list of his suggestions:
Thanks so much Joel for taking the time to talk to us! We eagerly await his return to the top of the leaderboard and look forward to seeing the rest of you challenging him!
Interview and writeup by David Chee