Spinoff - Cost Basis

[Forensicacctnt]

Taxpayer owned Company A shares (publicly held), spinoff distribution dated August 4, 2017, 1 for 11 shares of Company A. Received 4 and a fraction shares of Company B. I have the share prices of each company on the first trading date (August 7) after distribution.
I am trying to determine the cost basis of the fractional share (0.454545) where cash was received in lieu of this fractional share. Proceeds received 26.69. Is the cost basis date when shares of Company A were purchased? Or the date of the spinoff (August 4) or another date? How is the basis amount determined?
Thanks very much for the help.

[Forensicacctnt]

Thank You!

Taxpayer owned Company A shares (publicly held), spinoff distribution dated August 4, 2017, 1 for 11 shares of Company A. Received 4 and a fraction shares of Company B. I have the share prices of each company on the first trading date (August 7) after distribution.
I am trying to determine the cost basis of the fractional share (0.454545) where cash was received in lieu of this fractional share. Proceeds received 26.69. Is the cost basis date when shares of Company A were purchased? Or the date of the spinoff (August 4) or another date? How is the basis amount determined?
Thanks very much for the help.

I appreciate the information!

[Forensicacctnt]

Spinoff - Cost Basis

Is this perhaps related to MetLife / Brighthouse Financial events of 2017? ?

If so, many/most MET holders already had a ZERO cost basis in their original shares.
(Obviously, that would not apply to cost basis of any inherited MET shares.)

FE

Spinoff - Cost Basis

Yes, it is the MetLife/Brighhouse Financial of 2017. Thanks, I will use the cost basis of zero. The proceeds of the husband and wife's fractional shares was small, $29 and $26 respectively.

Thank you for your help.

[John of PA]

I'm curious, do the 2017 1099-DIV's that were always from Met Life now say Brighthouse as the payer?