U.S. stocks opened mixed Friday, the last trading day of the third quarter, as investors digested the country' s newly-released personal income and outlays data.

U.S. personal income increased 28.6 billion U.S. dollars, or 0.2 percent, in August, in line with market estimates, said the Commerce Department Friday.

In August, U.S. disposable personal income increased 14.9 billion dollars, or 0.1 percent, and personal consumption expenditures (PCE) increased 18.0 billion dollars, or 0.1 percent.

The PCE price index, the Federal Reserve's preferred measure of inflation, increased 0.2 percent. Excluding food and energy, the PCE price index increased 0.1 percent.

Meanwhile, investors were still assessing the tax reform framework released Wednesday, which will cut tax rates for businesses and individuals while lacks details on how to consolidate fiscal position in face of big tax cuts.

Shortly after the opening bell, the Dow Jones Industrial Average fell 35.91 points, or 0.16 percent, to 22,345.29. The S&P 500 edged up 0.22 point, or 0.01 percent, to 2,510.28. The Nasdaq Composite Index increased 10.95 points, or 0.17 percent, to 6,464.41.

On Thursday, U.S. stocks extended gains as investors assessed the country's newly-released framework on tax reform.