I received $20K stock (proceeds) from my company in 2018. The cost basis (box 1e) listed on the 1099-B is $16K. It is a Short term transaction with Box A checked. It is managed by Fidelity.

However when I go back to the Supplemental Information (not reported to the IRS) at the back of the Fidelity packet, the Adjusted Cost Basis is $20K. Likewise it indicated that $4K of Ordinary Income was reported.

Can I use the Adjusted Cost Basis in Form 8949 "Sales and Other Dispositions of Capital Assets" rather than what was reported in 1099-B?

Please advise. Your help is appreciated.

Basically, you need to follow th e instructions on Form 8949. On form 8949 part 1, you need to check one of the three options: 1 Short-term transactions reported on Form(s) 1099-B showing basis was reported to the IRS 2 Short-term transactions reported on Form(s) 1099-B showing basis wasn?t reported to the IRS 3 Short-term transactions not reported to you on Form 1099-B