topic Got no cost basis on 1099-B. If left blank on TT, it will list is as "info needed". Does this increase chance of audit? I couldn't get cost basis from Computershare. in Get your taxes done using TurboTax

Got no cost basis on 1099-B. If left blank on TT, it will list is as "info needed". Does this increase chance of audit? I couldn't get cost basis from Computershare.

pginotti — Mon, 23 Feb 2026 12:34:38 GMT

This was for a fractional sale, due to a merger. I'm wondering if I should just enter $0.0.

Re: Got no cost basis on 1099-B. If left blank on TT, it will list is as "info needed". Does this...

MinhT1 — Tue, 14 Feb 2023 15:43:59 GMT

Reporting a cost basis of $0 would not increase your chance of being audited. It will just increase your capital gain and cause you to pay more tax.

You can calculate the cost basis of the fractional share resulting from a merger.

For example, if you had 100 shares of ABC with a cost basis of $200. Then those 100 shares of ABC are exchanged for 5,25 shares of XYZ. So the cost basis remains the same for the 5.25 shares of XYZ at $200. Therefore, the 0.25 fractional share has a cost basis of $200/5.25 x 0.25 = $9.52.

Re: Got no cost basis on 1099-B. If left blank on TT, it will list is as "info needed". Does this...

pginotti — Tue, 14 Feb 2023 20:40:36 GMT

Thanks MinhT1,

Is there a concern if Computershare didn't report a cost basis and I show one?

Paul

Re: Got no cost basis on 1099-B. If left blank on TT, it will list is as "info needed". Does this...

GeorgeM777 — Tue, 14 Feb 2023 21:44:40 GMT

No, it is not uncommon that taxpayers need to make price adjustments in connection with mergers, acquisitions, reverse stock splits, etc. Make the necessary adjustment as suggested by @MinhT1. While the amount may have only a minor impact on your taxes, your return will be accurate as long as the adjustment is warranted.

Keep the records that you have in the event you may need to explain your justification for making the adjustment.

@pginotti