Wow, Scruffy! Thank you for your immediate, comprehensive response! Let me expound on the details.
The bond was slightly more than three years old when purchased and, in 1994, reporting requirements for the brokerage were not as comprehensive as they are today. I don't think that the imputed interest was reported for the first two decades or so.
Should I adjust the cost basis to include all imputed interest, meaning that the basis = the redemption price, considering that this is a Municipal bond and there should not be tax associated with the growth of my investment due to tax free interest?
