1099-B and Non covered shares

I purchased a few shares of a Utilities stock in the middle 1980’s and put it in the Utility company’s dividend reinvestment plan.  I left it alone and it grew. I sold it in 2022. I received a 1099-B for the sale of the stock from the brokerage firm that runs the plan for the Utility.

 

The shares were broken down in three categories on the 1099-B.

  1. Short term Covered Securities with proceeds and cost basis reported to IRS (3% of shares)
  2. Long term Covered Securities with proceeds and cost basis reported to IRS (32% of shares)
  3. Long term Non-Covered Securities with proceeds but no cost basis reported to IRS (65% of shares)

 

I was able to determine the cost basis for the non-Covered securities because I maintained records from the dividend reinvestment plan.  When I printed out my return which I e-filed, the return indicated that I did not have to attach any pdf.  However, when I was preparing the return, specifically the Form 8949 Sales of Capital Assets, the TurboTax program kept referring to providing additional supporting documentation for the non-covered shares to an IRS office in Austin, TX.

 

Can anyone confirm that I am required to report Non-Covered Securities cost basis supporting documentation to IRS, including what is required?