You would have a tax basis in your Theravance Biopharma common shares equal to the fair market value of such shares at the time of the distribution.
Your holding period for the Theravance Biopharma common shares received in the distribution would begin on the date of the distribution.
AzurRx BioPharma, Inc. - AZRX Stock Chart Technical Analysis for 01-07-2020
You should consult your own tax advisor as to the particular tax consequences of the distribution to you, including the applicability of any U.S. federal, state, local and non-U.S.
tax laws. For a more detailed discussion see "U.S.
Federal Income Tax Consequences" beginning on page 48.