Key Takeaways Shares of DocuSign and MDU Resources Group advanced Tuesday, a day after S&P Global announced changes to its indexes. DocuSign will replace MDU Resources Group in the S&P MidCap 400 index, while MDU Resources will replace Chuy Holdings in the S&P SmallCap 600 index. The changes will take effect before trading begins on Friday. Shares of DocuSign (DOCU) and MDU Resources Group (MDU) advanced 8% and 4%, respectively, soon after markets opened Tuesday, a day after S&P Global announced changes to ...