Agilent Technologies (A) spinoff of Keysight (KEYS) was tax-free, meaning the cost of your old Agilent shares should be split between your post-divesture Agilent shares and new Keysight shares.
That is, if the total cost of your old Agilent shares was $100 then the combined cost of your Agilent and Keysight shares should be $100, for example, your Agilent could basis might be reduced to $67 and your Keysight shares would be worth $33.
Aglient says:
For US federal income tax purposes, your aggregate basis of the common shares that you hold in Agilent and the new Keysight common stock received in the distribution (including any fractional share interest in Keysight common stock for which cash is received) will equal the aggregate basis in the Agilent common shares held by you immediately before the distribution, allocated between your Agilent common shares and the Keysight common stock (including any fractional share interest in Keysight common stock for which cash is received) you receive in the distribution in proportion to the relative fair market value of each on the distribution date.
Consult the Keysight Distribution Tax Basis Letter
