Legal Question in Real Estate Law in California

There is not any 90-day waiting period that I know of. I think you may be referring to the 90-day minimum that tenants have if a rental property is foreclosed on. Tenants have 90-days or until their lease ends, whichever is longer. If the property is owner occupied, in most cases, eviction proceedings can begin immediately after the trustee's deed is delivered. Why do you keep mentioning that the property has negative equity? That has nothing to do with eviction after sale. What it does mean, however, is that the holder of the 1st will most likely immediately begin their own foreclosure and so the HOA will wind up with nothing.

If the HOA has used nonjudicial foreclosure to collect upon a debt for delinquent assessments, then they are subject to a statutory 90 day right of redemption. (Civ. Code, sect. 1367.4 subd. (c)(4).)