Allowable business deductions from income?

[clintonrandall]

Can I write off a loss of non receipt of payment due to a firms bankruptcy?

[DDollar]

You can only write that off if you are an accrual based tax payer and you had already booked that payment as revenue.  The vast majority of small businesses are cash basis.  You would know if you were an accrual based tax payer.  More than likely you cannot take a deduction for the non receipt.