In November 2017, S&P Dow Jones and MSCI (SPDJI/MSCI) announced that the Global Industry Classification Standard, or GICS, telecommunication services sector would be broadened and renamed "communication services." The communication services sector will add select media, entertainment, and consumer Internet stocks from the consumer discretionary and information technology sectors to its current telecommunication services constituents.

In mid-January 2018, SPDJI/MSCI released a list of the largest companies affected by the GICS update. SPDJI/MSCI plans to release a full list of affected securities on 2 July 2018, and provide a finalized list of affected securities on 3 September 2018, before the GICS update takes effect after the market closes on Friday, 28 September 2018. This classification change will impact index funds that focus on the telecommunications, information technology, and consumer discretionary sectors.

Musical Chairs
Based on SPDJI/MSCI's updated press release, the S&P 500's communication services sector is set to add 19 new companies alongside AT&T (T, listed in the U.S.), Verizon Communications (VZ, listed in the U.S.), and CenturyLink (CTL, listed in the U.S.). To assess the impact of these additions, I calculated the stock weightings in Exhibit 1 using market capitalizations as of 31 December 2017. The bolded text represents new GICS industry groups, industries, or subindustries.