what is form 4952 investment interest expense deduction 
form 4952 investment interest expense deduction is a tax form distributed by the internal revenue service irs used to determine the amount of investment interest expense that can be deducted as well as any interest expense that can be carried forward to a future tax year 1 the irs has different rules taxpayers must follow depending on where the interest comes from and whether it is investment personal business or mortgage related if an investor pays or accrues interest on a loan and then uses the proceeds for several different purposes the taxpayer may have to allocate the interest to ensure that the right interest rule is used 2 who can file form 4952 investment interest expense deduction form 4952 investment interest expense deduction must be filed by individuals estates or trusts seeking a deduction for investment interest expenses that means if you borrow money for an investment you may be able to get a tax break you can claim the interest on the investment as a deduction interest income may result from money borrowed specifically to purchase investments like parcels of land commercial or residential investment properties stocks and non tax exempt bonds 