IT research firm Gartner (NYSE:ITwill join the S&P 500, replacing Dun & Bradstreet (NYSE:DNB), who drops to the S&P MidCap 400.

S&P MidCap 400 constituent Gartner Inc. (NYSE:IT) will replace The Dun & Bradstreet Corp. (NYSE:DNB) in the S&P 500, Dun & Bradstreet will replace Gartner in the S&P MidCap 400, and INC Research Holdings Inc. (NASD:INCR) will replace CEB Inc. (NYSE:CEB) in the S&P MidCap 400 effective prior to the open on Wednesday, April 5.

Gartner is acquiring CEB Inc. in a deal expected to be completed on or about that date pending final conditions.  Post-merger, Gartner will be more representative of the large-cap market space.  Dun & Bradstreet has a market capitalization more representative of the mid-cap market space.

Way back in the 1990’s D&B owned a chunk of Gartner equity.  How ironic that a former minority investment is now outperforming its former investor.

Source:  S&P Indices