I inherited accounts from husband. The brokerage firm told me distribution wasn't taxable BUT 1099-R has 2b checked "tax amount not determined." What do I do?

Typically distributions out of retirement accounts of any kind ARE taxable unless there's "basis" in the account - in which case some of the distribution would not be taxable - or the distribution is out of a Roth IRA.  Do you know the reasoning behind the brokerage firm's statement?

What code is in box 7?
Is the IRA/SEP/SIMPLE box checked?

code 4, yes the IRA/S/S box is checked

I'm looking at my notes.  I think that, in my grief,  the fact there would be no 10% Penalty for early withdrawal*  from this inherited account, I confused with the tax issue.  Obviously they are quite different issues.  *I am 56 y/o.

There is never any early withdrawal penalty on an inherited IRA.   It code 4 should prevent any penalty.

Sorry if I wasn't clear. My question was never about the penalty.  It was about whether the inherited funds were taxable after my husband died.  It appears they are.  Thanks.

For an IRA it is always "not determined" because the custodian does not know how many other IRAs you might have. if the decedent did not have a basis, it will all be taxable income.