Sale at 535 East 86th Street #16A

Possible, or the sellers are desperate to get out, and are resorting to an auction. I've always wondered what happens if you win the auction but don't pass the board. I assume the terms of the auction are such that you get your money back, but... ??

Were I in the market for that sort of thing, it's a desirable floorplan. It was built right at the end of that period when post-war apartments still had gracious layouts.

This co-op requires a 50% downpayment, though I'm not sure if an auction would require an all cash buyer anyway? This is what freaks me out about co-ops. If you get an unreasonable board that imposes a draconian down payment requirement, it severely damages your property value as your pool of buyers becomes substantially restricted.

CCL3, 50% down does reduce the pool, but mostly it reduces the pool of more risky buyers. Coop are just that...a collection of people who own a building together. I someone stops paying their common charges everyone else has to cover it. The tiny beauty of Coops is that you have some sense of who your neighbors are, at least financially. Condos are a much better investment but a slightly less desirable place to live as a primary residence. You could easily find yourself on a floor that has the feel of a rental building because every apartment is being rented. Think of Coops are like private clubs that set their own rules for membership. What about the buildings that have 50% down and demand 3X purchase price (liquid) post closing?

Most of the draconian boards are gold coast central park locations anyway.
Agree with Falco completely.
Now living in a small co-op 5 years, Ive come to realize I would never buy in a small (10 units or less) condo.
(I would in a large building)
Even with "stricter" financing rules peoples' situation(s) can change in less than a year.
It's happened to 2 "neighbors in my 5 years already. Thankfully, one got her act back together in less than 5 months because of international assets and the other is a death with some heir/ex significant other infighting without clear probate instructions.It will take some time to sort out but my building is ahead of any bank for any liens. No worries.

Units in buildings w/ 'draconian down payment' requirements typically trade at a discount to other similar units, just as land-lease units typically do -- finanical restrictions and risks are accounted for in the price.

Buildings where the unit price is fully unrelated to the restrictions (e.g., 'no financing permitted' + 5-10x liquidity post closing in some of those 5th Ave & Park Ave buildings) are mainly using the restrictions to provide greater protections, both in terms of who their neighbors are, and their financial situation: A 15 unit building on Park probably isn't carrying an enormous reserve account, because they know their owners can readily pay a one-off assessment for a significant repair or upgrade. The owners are fine with this, because they will make better returns on their cash than the co-op could by investing their reserve.

There are also Coops which have lowered their cash requirement over time - Like Stewart House @ 70 East 10th St, which was a 100% cash building, then 50% and I think now 40%.

Do purchase of foreclosure require 100% cash payment ; and do they allow people to view them prior to making bids, or do people have to buy without seeing the inside of apts?

I wouldn't assume that auction means foreclosure. The owner has no court cases active, so the bank's not suing him, and just re-fi'd in November. He's 70, and has places in Florida and the Hamptons, so probably just wants to unload this one.

It depends what you mean by the purchase of a foreclosure: if you mean at the foreclosure auction at the courthouse or where it is being held, then in most cases yes you have to buy it sight unseen (unless you have some other way of seeing it - the bank doesn't make it available to be seen before the auction). You also have to buy it subject to any occupancy, maintenance arrears and all cash in most cases).