Let us say i am a trader in the eyes of tax office, does it mean...

Let us say i am a trader in the eyes of tax office, does it mean my loss is 18000 or 2000?

i really appreciate if you can anwer this one. My accountant put it as 18000 but i asked him later over the phone to change it to 2000 dollars as i do not want to get in trouble with tax office but at the same time i might miss a big fund return rightfully.

My drama is that i do not my accountant is doing the right thing or not and at the same time i do not know much about the tax rules.