(Bloomberg) — The first reboot of S&P 500 Index group weights in almost two decades has arrived, shaking up stock portfolios and conjuring an industry out of REITs that will infuse at least one lightweight ETF with sudden riches.

With the push of a button, index overseers are breaking the stock market’s model of the financial industry in half, dividing REITs from banks and brokerages and giving them their own slot in the S&P 500. The biggest benchmarks will expand their tally of major industries to 11 from 10, reclassifying companies that have been among the bull market’s best performers.

Subscribe Now

Access to premium content including in-depth coverage of mutual funds, hedge funds, 401(K)s, 529 plans, and more.

3-Week Free Trial

Insight and analysis into the management, marketing, operations and technology of the asset management industry.