We looked into Arbitrum’s TimeBoost auction in this new short paper [2511.18328] TimeBoost: Do Ahead-of-Time Auctions Work?
TimeBoost runs an “express lane” auction every minute and the winner of the auction has their transactions “time-boosted” by 200 ms during the next minute.
Evaluating the performance of the TimeBoost tx policy is an interesting exercise in itself, but I think the results can be insightful beyond this particular context: a main finding of the empirical analysis is that bids for the fast-lane are a reasonably good predictor of longer time average arbitrage profits, but a very noisy predictor of one minute profits. Thus, auctioning rights for earlier transaction execution ahead-of-time instead of just-in-time arguably lowers auction efficiency and revenue.
This might also cast some doubt on the idea of AOT slot auctions as a suitable market structure for block building in Ethereum.
As always, comments are very welcome.