
Microsoft Corp. shares slipped below the psychologically important $500 mark during Tuesday’s session, touching their lowest level this month. The drop adds to a steady retreat since late July, when the stock last tested support near $517. The pull-back comes against the backdrop of starkly different valuation eras for the software maker. Microsoft once traded at about 81 times forward earnings during the dot-com boom in 1999, then troughed near 8.3 times in 2011. While its current multiple remains well above the historical low, the latest slide underscores investors’ sensitivity to technical levels after the stock’s strong run earlier in the year.

