We sold some 3M stock. Turbo is asking for the "cost or adjust basis" on our 1099-B. But the form says "unknown." the box in turbo won't accept this. Please help. Thanks.

[KenH1]

Brokerage statements will not always report the cost basis and/or sales category. The IRS is receiving the 1099-B information from the broker, but is relying on you to report the correct cost basis and category.

For unreported cost basis:

Make a reasonable estimate, based on old trade confirmations or historical prices from a source such as www.finance.yahoo.com 

For unreported sales category:

If you held the security less than one year, use code C (short-term, not reported)

If you held the security more than one year, use code F (long-term, not reported)