Sometimes, a Manifold question is isomorphic to a financial asset. For example, the question "What will be the price of the S&P 500 in one year?" is identical to an S&P 500 future dated to one year. On those sorts of questions, is Manifold better-calibrated than financial markets?

This question is non-trivial to answer because I don't know how to extract Manifold-style binary predictions from financial markets (or vice versa). And even if I did, going through a bunch of markets and calculating their calibration would be some amount of work.

I will resolve this question whenever someone (a) comes up with a reasonable idea for how to compare Manifold vs. financial markets and (b) actually does the comparison. Whoever does this will get to make mana by insider-trading on this question.