LastWeekTonight
1 HN recommender · recommended in 3 months, 2026
32:59 · 4.4M views · Apr 20, 2026
John Oliver's Last Week Tonight segment examines prediction markets such as Polymarket: the legal and moral questions, weak regulation, and insider trading and manipulation concerns.
HN cites it in prediction-market threads as an accessible critical overview, including the Polymarket CEO's remarks on insider trading.
4 comments from Hacker News
John Oliver had a segment on prediction markets this week. It covers insider training and opportunities for blatant manipulation like this, well worth checking out. The example in the Last Week Tonight segment was betting on dildos being thrown on court during a WNBA match. And then travelling to the match to throw the dildo. [0] this video
The social costs of gambling, particularly compulsive gambling, cannot be so easily dismissed. I would encourage you to visit your local Gamblers’ Anonymous group or seek out addicts’ stories of loss and despair to get a fuller picture of it. As for expected losses, yes, there is a legitimate trade in securities in which some will earn money from their investments and some will lose money from them. Securities like stocks, bonds, derivatives, commodities, and so forth have real things of value underneath them, like business income and stuff made from the commodities. (And it’s not a minority who earn long-term gains from these; there are entire pension schemes covering millions of people that are funded from them from 401(k)s to TIAA.) Predictions, on the other hand, are valued solely based on human estimations. That’s not in itself a problem, but the issue is that predictions markets, unlike securities markets, are not regulated. Compare the fact that insider trading of securities is illegal and punished with fines and imprisonment, while in a predictions market, insider trading is incentivized and occurs with unsurprising frequency (e.g. big wins by a privileged few who bet on the timing of military actions). Market manipulation is the problem, not that some will make the wrong bets. The rules and conditions of the game must be fair, even if the outcome of the game isn’t. And I haven’t even begun to mention the issue of the things you can bet on in prediction markets that a
Genuine question: do prediction markets open up a new revenue stream for TheNumbers.com? Specifically: they suspect that the motivation for trying to hack their site (for at least some people) is that they wanted early access to numbers that folks were betting on in prediction markets. Since they've got those numbers they can just bet on them, then benefit from their perfect knowledge. On the one hand this does seem incredibly unethical (it's clearly insider trading). On the other hand the CEO of PolyMarket has said that insider trading is part of the point of PolyMarket: this video
John Oliver just did a segment on prediction markets. this video Turns out the US federal regulator is not doing their job, and is actively trying to prevent US states from imposing regulations.