As we wrap up this rather short week on the markets, one trend we'd like to highlight is the increasing dispersion we're seeing between the various sectors of the S&P 500 so far this year. Remember how tightly stocks moved last year?

Between the two European crises and the effects of the Fed's QE2 program on stocks last year, it seemed everyone was moving up and down together in one tight pack, as markets responded to top-down macro factors -- it hardly seemed to matter whether you were a medical device maker or an oil rig...