What is a PFIC?

I find foreign tax reporting so complicated, and yet we need to know the basics, I know.

So my question is, what is considered a PFIC? Is it a publicly traded foreign mutual fund owning publicly traded stocks and bonds? Or is it a foreign mutual fund owning private stock or bonds?

The more I know the more I realize how little I know about taxes...

https://www.law.cornell.edu/uscode/text/26/1297

What helped me when working on deciding what was a PFIC is to realize that the Passive Foreign Investment Company is a trick. The trick being that foreign mutual fund type vehicles are generally organized as companies.
My issue was with a bunch of mutual funds in the UK in a ISA (this is just a tax protected savings account unrecognized by the US).
So the funds in question were ICVCs or OEICs. When I looked at their structure they were companies.
So find out what the mutual funds really are.

Here's a link for you, it may help.....

https://expattaxtools.com/

Thank you all, and especially Bob A for the very useful website.