FACTS:
- You write a put.
- It gets exercised on Dec 18th, 2011.
- You are now long 1,000 shares @ $100 each ($100,000 of stock) and there is a $100 commission for the assignment. Your cost basis is $100,100.00.
- You sell half of the shares on Dec 31, 2011 and the other half the next day...