Stocks ended a wobbly week broadly lower, with a good part of Friday’s loss attributable to weakness in big technology companies like Apple and Amazon.

       The S&P 500 index fell and marked its first weekly loss after three weeks of gains. Small-company stocks continued to badly lag the rest of the market, a signal that investors could be becoming more concerned about how strongly the economy will keep growing in coming months. Treasury yields remained relatively low, another sign of caution among investors.

       On Friday:

       The S&P 500 fell 32.87 points, or 0.8%, to 4,327.16.

       The Dow Jones Industrial Average fell 299.17 points, or 0.9%, to 34,687.85.

       The Nasdaq fell 115.90 points, or 0.8%, to 14,427.24.

       The Russell 2000 index of smaller companies fell 27.06 points, or 1.2%, to 2,163.24.

       For the week:

       The S&P 500 is down 42.39 points, or 1%.

       The Dow is down 182.31 points, or 0.5%.

       The Nasdaq is down 274.68 points, or 1.9%.

       The Russell 2000 is down 116.77 points, or 5.1%.

       For the year:

       The S&P 500 is up 571.09 points, or 15.2%.

       The Dow is up 4,081.37 points, or 13.3%.

       The Nasdaq is up 1,538.96 points, or 11.9%.

       The Russell 2000 is up 188.38 points, or 9.5%.