U.S. stocks are opening higher on Black Friday, the unofficial start of the holiday shopping season.

In the first few minutes of trading, the Dow Jones industrial average is up 61 points at 12,898. The Standard & Poor's 500 index is up six at 1,397. The Nasdaq composite index is up 17 at 2,943.

Retail is a key driver of the nation's economy. Consumer spending accounts for about 70 percent of U.S. economic activity. Traders will be looking for signs about how enthusiastically Americans are spending. That could reflect the momentum of the economic recovery.

The Friday after Thanksgiving is known as Black Friday because it begins the period in which many retailers turn profitable for the year.

The market will close early, at 1 p.m. EST.