Executive Mosaic’s GovCon Index registered its largest single-day loss this week and a massive 9.31% weekly loss. Besides the 6.2% plunge Thursday, the substantial gains (+4.7%) from the previous record-setting week were gone. The index, which tracks the stock performances of 30 major government contractors, closed 1.78% lower at $5,160.07 Friday. Major U.S. stock benchmarks