Here is what I think I know:
If you exercise a put option and sell the underlying securities, the premium you paid for the option (plus commissions and fees) reduces the amount you realize on the sale of the underlying securities. Determining whether you have a short-term or a long-term gain or loss depends on when you purchase the underlying securities in relation to when you bought the put. If you sell securities that you had held long term at the time you bought the put, you will have a long-term gain or loss.
If you sell securities you had held short term at the time you bought the put, or if you purchased the securities after you bought the put (but before you exercised the put), the transaction will be treated as a short sale. That is, your holding period for the securities starts on the date you exercise the option, regardless of when you actually bought them.
If the put is a married put, the gain or loss will be short-term or long-term, depending on how long you had held the securities before you exercised the put.
I 'm looking for something to clarify how NUA assets are handled with regard to date of acquisition. While I've been holding the assets in a 401k plan for a very long time, I am distributing them out as NUA in the near future so one might say they I've "held" them short term, or that I acquired them after the PUT was purchased.