Unknown cost basis of a spinoff and unknown basis date

[saljflsajal]

How do I locate an unknown cost basis of a spinoff.
How do I locate the basis date?

 

[sjaljalkfls]

Assuming that you are talking about a publicly traded security, you can contact investor relations and/or your brokerage firm to locate info on the spinoff date and spinoff details. From there you should be able to back into your cost basis.