On my return I received a credit for the entire amount I paid to Israel for the ZIM dividends. My understanding was that you receive a credit equal to the amount you would have paid on the dividend income if it was a US based dividend, i.e. no double taxation. So I did some experimenting in TT by removing some other income until I was in a lower tax bracket, and sure enough, the credit was reduced to something less than 100%. TT does all the calculations, but you must choose the tax credit instead of the deduction. You can also carry forward the unallowed credit but I don't know if you can eventually recapture that credit.