Covered means basis is reported to the IRS. Noncovered means basis is not reported to the IRS. The 1099-B specifies this in a couple of ways... sometimes you will see a box checked in the covered/uncovered column. Often, you will see a title above your stock sales that would say "Long-term with covered" or "Long-term with basis reported to the IRS"... look for those descriptions to determine the sale category.
What if the 1099B has some entries that have Box 5 listed with a Yes and some with a no. Should this be considered covered or non covered. All of the entries are more than 9 years old.
Using a "yes" or "no" is an unusual way of reporting the information. Brokers did not have to provide this information to investors until January 1, 2011. It makes sense then that all of the events are more than nine years old.
Box 5 is checked if it is a non-covered security. Yes means that the box is checked. See page 5: IRS Instructions 1099-B