Hyatt will join S&P MidCap 400; shares rally after hours

Hotel chain Hyatt Hotels Corp.
H,
+0.04%
will replace National Instruments Corp.
NATI,
+0.57%
on the S&P MidCap 400 before the opening of trading on Thursday, S&P Dow Jones Indices said on Monday. The change is taking hold after Emerson Electric Co.
EMR,
+0.87%
agreed to acquire National Instruments. Shares of Hyatt were up 5.3% after hours on Monday.