When box 5 is checked on Form 1099-B it means that your sale(s) was for a non-covered security. In these cases, the broker is not required to report: 1b - date acquired, 1e - Cost or other basis, 1f - Accrued market discount, 1g - Wash sale loss disallowed, box 2 Long Term, Short Term, or Ordinary gain or loss. You report those sales on Form 8949 just like you would Covered Transactions, even if the broker doesn't report the information on Form 1099-B.