Which question in MO has had maximal total bounties among other questions? I mean the total bounties which are given by the asker or other participants.
The Data Explorer is the perfect tool for this kind of questions. The highest possible single bounty is 500 points. (For details of bounties, see this and this help page.) See the query Questions that received a lot of bounty. It gives a list of questions that have received more than one bounty, sorted by total amount. These exceed 500 points:
- When does a modular form satisfy a differential equation with rational coefficients?, 1000 points (2 bounties)
- The error in Petrovski and Landis' proof of the 16th Hilbert problem, 700 points (3 bounties)
- Distributivity of group topologies on $\mathbb Z$, 600 points (2 bounties)
- Godel on recursion-theoretic hierarchies, 550 points (2 bounties)