Say a trader received a K1 from a prop firm for 50k. This trader found $6,000 worth of write offs. The standard deduction this year say is $5700. So, what is my tax liability? 50,000 - 6000 - 5700 ___________ 38,700 or because the write off was taken, you CANNOT take the standard deduction so your tax liability would be... 50,000 -6000 ____________ 44,000