Stock question

CA. I'm part of a joint account in a stock-trading service. Do we both need to declare our losses and gains or only one of us need to do so for our tax forms?

The rule is that the person entitled to the gains and losses under local law is the person who must declare the income and loss. If the funds belong to only one of you, then that person’s SS # should be given for 1099 purposes. As a practical matter, if either of you declares the entire amount or if you split it, as long as the entire amount is declared, that will usually satisfy the IRS.