Shares of Irvine medical device maker Masimo Corp. rose Thursday on news that the company is being added to Standard & Poor’s MidCap 400 stock index.
Masimo shares closed up 6% in Thursday trading with a market value of $1.56 billion.
The company, which makes patient monitors used in hospitals and other settings, is set to be added to the S & P; MidCap 400 on Dec. 18.
Masimo is replacing PDL BioPharma Inc. of Redwood City on the index.
PDL is being removed from the index with a spinoff of its biotechnology operations in a deal expected to be closed on or about that date.
Joining an S & P; index typically drives a surge in stocks of added companies as mutual funds that mimic the indexes buy shares.
Thursday’s gain in Masimo’s shares likely came from investors betting on a wave of mutual fund buying between now and Dec. 18.
