MASIMO CORP

Ticker: MASI CUSIP: 574795100 Class: Common Stock

WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC's Holding History (CIK: 0001644956)

Note: Option positions (PUT/CALL) are excluded.

Q2 2021

Shares 431,775 Value ($000) $104,684 Avg Close $228.17 Range $205.10 - $250.49

Q1 2021

Shares 438,283 Value ($000) $100,656 Avg Close $251.21 Range $217.65 - $284.86

Q4 2020

Shares 439,444 Value ($000) $117,938 Avg Close $249.38 Range $218.23 - $273.33

Q3 2020

Shares 445,188 Value ($000) $105,091 Avg Close $224.17 Range $203.81 - $248.88

Q2 2020

Shares 452,371 Value ($000) $103,136 Avg Close $219.47 Range $173.15 - $258.00

Q1 2020

Shares 804,330 Value ($000) $142,463 Avg Close $171.51 Range $143.90 - $187.85

Period	Shares	Value ($000)	Average Close	Price Range
Q2 2021	431,775	$104,684	$228.17	$205.10 - $250.49
Q1 2021	438,283	$100,656	$251.21	$217.65 - $284.86
Q4 2020	439,444	$117,938	$249.38	$218.23 - $273.33
Q3 2020	445,188	$105,091	$224.17	$203.81 - $248.88
Q2 2020	452,371	$103,136	$219.47	$173.15 - $258.00
Q1 2020	804,330	$142,463	$171.51	$143.90 - $187.85