The S&P and  Dow Jones Indices have made adjustments to the market cap definitions of its indexes that have resulted in some ticker shuffling.

Effective today, the S&P 500 has a market cap guideline of $6.1B or greater (up from a previous $5.3B). In addition, the S&P MidCap 400 now ranges in market caps from $1.6B to $6.8B (up from $1.4B-$5.9B), and the S&P SmallCap 600 goes from $450M to $2.1B (up from $400M-$1.8B).

S&P says the moves are due to a market that has risen 5.5% this year and 19% over the past 12 months. The changes are effect before the open March 20.

Three members of the 500 are switching places with three in the MidCap 400, and three more in the 400 will trade with three constituents of the SmallCap 600.

Moving from MidCap to the S&P 500: AMD (up 3.2% after hours); Raymond James Financial (RJF, up 0.9% after hours) and Alexandria Real Estate Equities (ARE, up 1% after hours). Moving to the MidCap 400 from the 500 to make room for them: Urban Outfitters (URBN, down 1.3% postmarket), Frontier Communications (FTR, down 0.4% late) and First Solar (FSLR, down 1.9% postmarket).

Meanwhile, moving up to the MidCap 400 from the SmallCap 600: TTWO, MASI, COHR. Moving down to the SmallCap 600 to take their place: FOSL, DNR, VSTO (up 0.2% after hours).