Underneath the sharp stock market rally that has surprised investors this year, a trend has played out that gets little attention: the very top end of the S&P 500 has been driving all the gains (namely, large-cap tech stocks like Microsoft Corporation (With combined experience of covering technology companies on Wall Street and working in Silicon Valley, and serving as an outside adviser to several seed-round startups, Gary Alexander has exposure to many of the themes shaping the industry today. He has been ...