When filing your tax returns as married filing separately, how do you split the joint brokerage accounts with interest and capital gains?

[robertkat]

Example: we have a brokerage account with Fidelity acct xyz, which is a joint account with both our names on it. It has $1,000 of interest, $2,000 dividends and $5,000 longterm cap gaines. Is there a special form to split this, or does the IRS look at both returns to make sure each party submitted their half?

[MindyB]

It depends on your state laws.

If you live in a community property state, each spouse reports half of the joint income on their return. If you don’t live in community property state, prorate the  income based on your portion of ownership of the account throughout the year.

See Publication 555 (12/2024), Community Property for more information.