Largest HOA assessment I've heard of is, "Sorry, you're SOL for the full value of your property"
It was a case example in my risk management class. Background was some bored retiree rube ran for and was elected to be the Treasurer of the HOA. After a little while in the role, he ended up having a friend who happened to be an insurance agent (don't we all have "that guy/girl"?) who could "beat his rate" for whatever the HOA was paying for master insurance, and give him a bit of a kickback on his commission. You can probably guess where this is going.
"Buddy" beats his rate, never mind it is inferior coverage. Treasurer cancels old insurance (as in stops paying premiums). Major fire happens, levels all the units. The HOA goes to put in the insurance claim and come to find out, they aren't fully covered like they used to be (money saved by going from replacement cost to depreciated value coverage), and end up short to the tune of having to level a special assessment for $10k per owner that should have been $0. Owch, right?
The owners aren't happy that, without authorization and against the bylaws, the Treasurer changed policies. They petition the original insurance company to reinstate the policy under the appeal that the Treasurer wasn't authorized to cancel the policy. Original insurance company points to rule that if the premiums aren't paid, the policy is void. Oh well, it was worth a shot right? Guess we'll all have to pay that $10k, right?
It gets worse. 2nd insurance company finds out from the 1st insurance company that the Treasurer wasn't authorized to purchase a policy. 2nd insurer points to a clause in their agreement that they're conducting with a "duly authorized representative of the HOA", and as the Treasurer had no authority to buy the policy, it too is void. Premium returned.
Yeah. That rube retiree's $250k in wealth (other than his freshly burned down condo now worth $0) would have been just about enough to pay to clear all the rubble from the lots so they could sell the land...except it was 100% protected from judgement because it's in 401ks/IRAs. Each and every unit owner had to eat a 100% loss, on what were about $300k units.
HOAs and their boards are a mother.