If your insurance policy is "unit linked" - meaning that there is an underlying value calculation that is tied to an index of some sort, then it's a PFIC. It isn't always very easy to tell, but the most common policies that fall under this definition are those from the UK, Singapore, or India from AIA, ICICI, Prudential, and Aviva. Not all policies issued in those countries or from those insurers are PFICs, and there may be others I've not mentioned which are PFICs.
If in doubt, report the asset or find a tax professional who specializes in PFIC reporting to assist. There can be a lot of penalties if this isn't properly reported and as you can see looking at the form it's not always straightforward or the language used may not match, as in the case of "shareholder".
If you do find that you need to report the insurance on Form 8621 the policy owner and/or the insured would be the "shareholder" - many times those are one in the same but where they differ the contract terms will dictate the individual that is the "shareholder" for purposes of this form.
Part I would apply and you would be looking for "units" most likely in stead of "shares" to answer these questions. The default for question 5 is 1291 but you may be eligible to elect mark to market treatment (1296). Parts II and IV may or may not apply depending on your situation.
Depending on the nature of the information reported on your annual statements, it is possible that you may need additional information to determine unit values - sometimes this information isn't always easy to obtain. Some insurers have "supplemental PFIC" information available for the asking or at their websites and others are unable to give you anything more than your annual statement.
Usually, I recommend that everyone filing this form seek professional guidance, at least for the first year, as that is often when certain elections favorable to the taxpayer must be made. The form isn't user friendly and it's really best completed by someone with specific experience filing the form.
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