I purchased stocks with TD Ameritrade in about 2001 to 2002. I sold them tis year. My TD Tax form dose not list cost basis. what can I do?

You enter the basis from your records of your purchases. If you do not have records of the purchases, ask TD Ameritrade if they have a record of your purchases. They might have the records, even though they didn't put the information on your tax form. As a last resort, make your best guess about the date of each purchase, and use a web site that provides historical stock prices to find the market price of the stock on that date.

you must supply the basis from your own well kept records.

Otherwise, if you are audited, IRS will deny your basis claimed and use a basis of zero.