“substantially identical” and wash rule
From what I have read separate companies are always considered not identical unless there is an announced merger that ties their prices together.
The IRS generally even considers common and preferred to be not identical.
F&F is a special case where they have common oversight... so if you consider both to be subsidiaries of treasury or fhfa - then maybe they are identical, but even subsidiaries of a company that each have stock are not identical.
Twins - yes, with same guardian raising them these last 10 years, same home rules, same annoying uncles and aunts in congress - but not identical twins.
My wash error was forgetting that I had bought in one account and sold in another... had been hoping to take that loss on those $40 shares last year. Oh well... they are (maybe) gone this year... hmm I forget to check all my accounts for overlapping buys/sells. On the good side - I do remember Schwab giving me some sort of alert about this when I did the trade, but most of my trading is contrary to common fiduciary responsibility so I tend to ignore all those warnings when I trade.