Your strategy doesn't work on sportbooks to begin with, because bookmakers don't move the odds with the action.
That is, there is no such phenomenon as "the over is exciting therefore overpriced". Bookmakers price purely based on facts and statistics. Their pricing isn't affected by excitement nor by how many people are betting a certain way.
A bookmaker is a market maker, and they ideally want to end up with no net interest in a position. They then take guaranteed profit in the bid-ask spread, which in sportsbooks is the 'vig'. Bookmakers who adjust their odds in real-time don't have to be particularly clever about the fundamentals, just responsive to the competing demands on either side.
A bookmaker who intentionally takes a position on a game is the equivalent of a proprietary trader or hedge fund. It's potentially more profitable, but it's also adversarial against 'sharp' traders.
Bookmakers who set odds at the beginning and don't move with the action must set larger bid-ask spreads to compensate.
If this were true, lines would never move unless there was breaking news, but we see lines move all the time without there being any material change to those "facts and statistics".
Without there being any material change you can see. If you had access to all the tips and data and insider information that sportbooks operate with, you could be a bookmaker too.
Can you give an example of what you're talking about here? Because it sounds like you're accusing these large publicly trade companies of participating in organized crime. There is regulation when it comes to sports betting that doesn't exist with general prediction markets. An athlete can't just feed a sportsbook "insider information" in the way you're suggesting. The only private info that they are supposed to have is better behavior details that you claim doesn't factor into their decisions.
Where did that entity get that information, and how are they right so often? Your guess is as good as mine. I'm not accusing anyone of anything.
Well that's the source of our confusion then. I agree with this, but it conflicts with what you said a few comments up:
>because bookmakers don't move the odds with the action.
Different from a prediction market like Polymarket or Kalshi whose income probably comes mostly from transaction fees rather than house edge. Otherwise these platforms wouldn't welcome bots so much. Bots => efficient pricing + transaction volume => profit for them
Yes, you can find positive EV trades on Wall Street as well. I've been diving into this a lot lately, all I can say is it's 10X harder to find strategies that work on Wall Street than prediction markets.
With one exception.
The one easy long-lasting anomaly to exploit on Wall Street which actually does NOT exist on prediction markets: "American stocks go up most of the time". This is actually a massively exploitable structural anomaly (you just buy and hold forever and effectively reap the rewards of a biased coin) and the source of the anomaly is mostly US monetary policy, US foreign policy, and US tech expertise put together. However, it still is an anomaly. The thesis that SPY will continue going up forever is also predicated on these things continuing to work the way they have in the past.