Legal Question in Wills and Trusts in Illinois

Re: Taxes After Death

Unless you have a court declare that this is legally a probate estate asset, the answer is no. Per joint tenancy, the account legally became yours upon your mother's death, and you cannot 'assign' *your* income to someone else. You are certainly free to make gifts to your siblings (if in excess of $10k each you need to file a gift tax return for yourself - no tax due if under $675k lifetime), and you can yourself calcultae the tax you paid on it and subtract it from their "share", as you see fit. But short of a court finding, you are the legal owner of the account and are under no legal responsibility to share it with your siblings. You mentioned that you are sharing it per the will, but of course this is technically not the case since the will does not control joint tenancy accounts.

Re: Taxes After Death

Let's back up. If you are a joint tenant on the account, that money passes to you as survivor, and it is not controlled by her will.

There are two possibilities of the will governing.

One is a court fight in which your siblings prove that you were on it for convenience only and it belongs to the estate, in which case the 1099 would go to the estate.

The other is if you voluntarily recognize that that was her intent and you distribute it according to her will. In that case, the simplest thing is to withhold a little from their shares -- enough to pay the tax on the interest -- and just treat it as your own.