S&P Global's stock dropped as much as 18% in pre-market trading after the financial information services firm issued a full-year adjusted profit forecast that fell short of Wall Street's expectations.
The news also weighed on shares of peers: MSCI declined 3.4%, Moody's fell 6.5%, FactSet dropped 4.9%, and Nasdaq decreased 3.8%.
In Europe, London Stock Exchange Group's shares fell as much as 2.7%, while RELX PLC dropped up to 2.8%.
Wolters Kluwer saw a maximum decline of 2.4%, and Deutsche Börse fell as much as 1.3%.