That is incorrect. the instructions for 4a & 4b for form 8960
Line 4a—Income From Trades/Businesses, Rental Real Estate, Royalties, Partnerships, S Corporations, and Trusts
Enter the following amount from your properly completed return.
• Schedule 1 (Form 1040), line 3.
• Schedule 1 (Form 1040), line 5.
Use line 4b to adjust the amounts included on line 4a, for gains and losses that are excluded from the calculation of net investment income. Enter the amount of gains (as a negative number) and losses (as a positive number). Enter the net positive or net negative amount for the following items included on line 4a that aren’t included in determining net investment income.
Net income or loss from a section 162 trade or business that’s not a passive activity and isn’t engaged in a trade or business of trading financial instruments or commodities.
so 4a should be $4K ($13K-$9k), 4b should be $9K as a positive number making line 4c $13K
not sure what worksheet you entered the business loss on. check your entries.
also check what's on schedule 1 lines 3 and 5
