equal weighting the s p 500 vs the s p s p 400 and s p 600 why consider s p 400 and s p 600 why consider sector ysis of the s p midcap 400 the s p midcap 400 an overlooked gem the s p midcap 400 equal weighting the s p 500 vs the s p s p 400 and s p 600 why consider equal weighting the s p 500 vs the s p inside out squareplugs sp400 sp500 the s p midcap 400 equal weighting the s p 500 vs the s p