The technology sector was by far the best performer of the S&P 500's SPX, +1.06% 10 sectors during the third quarter, with the SPDR Technology Select Sector ETF XLF, +1.79% running up 10.5% over the past three months. That would be the best quarterly performance for the tech-sector tracker (XLK) since it shot up 10.8% during the fourth quarter of 2013. Apple Inc.'s stock AAPL, +0.91% the XLK's most heavily-weighted component, surged 18.5% since the end of June, marking the best quarterly performance since the second-quarter of 2014. Among other XLK heavyweights, shares of Microsoft Corp. MSFT, +0.49% climbed 12.7%, Facebook Inc. FB, +0.28% ran up 12.5%, AT&T Inc. T, -0.05% dropped 5.8% and Alphabet Inc. GOOGL, +0.54% tacked on 14.8%. The second-best sector industrials, with the SPDR Industrial Select Sector ETF XLI, +1.16% up 4.5%, while the worst performer was untilities, as the SPDR Utilities Select Sector ETF XLU, -0.70% dows 6.7%. Meanwhile, the S&P 500 gained 3.6% during the third quarter.