There is a long list of 79 institutional holders of MASS within the last two holding periods in our database of 13F filers, so we've sorted through to present to you just the top 50 institutional holders of MASS by largest to smallest position reported in the institutional investor's latest 13F filing. In the institutional-holders-of-MASS table below, the initial column indicates the name of each top institutional holder of MASS, with a link to that fund's top holdings. The next columns indicate the amount of MASS stock held by each of the institutional holders of MASS, followed by the MASS position size held by the institution, and finally the date of the quarterly 13F filing period the holdings data represents for that institution.

Holder	Amount	Position Size ($ in 1000's)	As of
ARK Investment Management LLC	4,048,938	$30,569	03/31/2024
MASS	4,048,938	$30,569	03/31/2024
Granahan Investment Management Inc. MA	2,038,658	$22,874	12/31/2023
MASS	2,038,658	$22,874	12/31/2023
Ameriprise Financial Inc.	1,889,626	$21,202	12/31/2023
MASS	1,889,626	$21,202	12/31/2023
BlackRock Inc.	1,786,753	$20,047	12/31/2023
MASS	1,786,753	$20,047	12/31/2023
Vanguard Group Inc.	1,744,330	$19,571	12/31/2023
MASS	1,744,330	$19,571	12/31/2023
Eventide Asset Management LLC	1,430,995	$16,056	12/31/2023
MASS	1,430,995	$16,056	12/31/2023
Iron Triangle Partners LP	1,284,947	$14,417	12/31/2023
MASS	1,284,947	$14,417	12/31/2023
Fred Alger Management LLC	1,210,419	$13,581	12/31/2023
MASS	1,210,419	$13,581	12/31/2023
Platinum Investment Management Ltd.	781,871	$8,773	12/31/2023
MASS	781,871	$8,773	12/31/2023
AWM Investment Company Inc.	653,468	$7,332	12/31/2023
MASS	653,468	$7,332	12/31/2023
Nikko Asset Management Americas Inc.	582,034	$6,536	12/31/2023
MASS	582,034	$6,536	12/31/2023
Sumitomo Mitsui Trust Holdings Inc.	582,034	$6,530	12/31/2023
MASS	582,034	$6,530	12/31/2023
Tao Capital Management LP	568,981	$6,384	12/31/2023
MASS	568,981	$6,384	12/31/2023
Geode Capital Management LLC	518,589	$5,819	12/31/2023
MASS	518,589	$5,819	12/31/2023
State Street Corp	407,313	$4,570	12/31/2023
MASS	407,313	$4,570	12/31/2023
Sands Capital Ventures LLC	237,258	$2,662	12/31/2023
MASS	237,258	$2,662	12/31/2023
Northern Trust Corp	180,928	$2,030	12/31/2023
MASS	180,928	$2,030	12/31/2023
Charles Schwab Investment Management Inc.	180,661	$2,027	12/31/2023
MASS	180,661	$2,027	12/31/2023
Dimensional Fund Advisors LP	110,955	$1,245	12/31/2023
MASS	110,955	$1,245	12/31/2023
Nuveen Asset Management LLC	101,636	$1,140	12/31/2023
MASS	101,636	$1,140	12/31/2023
Tang Capital Management LLC	100,000	$1,122	12/31/2023
MASS	100,000	$1,122	12/31/2023
Renaissance Technologies LLC	96,900	$1,087	12/31/2023
MASS	96,900	$1,087	12/31/2023
Bank of New York Mellon Corp	92,195	$1,034	12/31/2023
MASS	92,195	$1,034	12/31/2023
New York State Common Retirement Fund	74,033	$831	12/31/2023
MASS	74,033	$831	12/31/2023
Morgan Stanley	70,325	$789	12/31/2023
MASS	70,325	$789	12/31/2023
Bruce & Co. Inc.	68,286	$766	12/31/2023
MASS	68,286	$766	12/31/2023
Citadel Advisors LLC		$740	12/31/2023
MASS	53,863	$604	12/31/2023
Call	13,000	$146	12/31/2023
Put	900	$10	12/31/2023
Bridgeway Capital Management Inc.	65,500	$735	12/31/2023
MASS	65,500	$735	12/31/2023
LPL Financial LLC	52,456	$589	12/31/2023
MASS	52,456	$589	12/31/2023
Bank of America Corp DE	45,271	$508	12/31/2023
MASS	45,271	$508	12/31/2023
Rhumbline Advisers	37,029	$415	12/31/2023
MASS	37,029	$415	12/31/2023
Barclays PLC	30,113	$338	12/31/2023
MASS	30,113	$338	12/31/2023
Susquehanna International Group LLP	29,731	$334	12/31/2023
MASS	29,731	$334	12/31/2023
Envestnet Asset Management Inc.	28,932	$325	12/31/2023
MASS	28,932	$325	12/31/2023
Goldman Sachs Group Inc.	28,279	$317	12/31/2023
MASS	28,279	$317	12/31/2023
Arete Wealth Advisors LLC	27,958	$314	12/31/2023
MASS	27,958	$314	12/31/2023
Primecap Management Co. CA	26,870	$301	12/31/2023
MASS	26,870	$301	12/31/2023
Alliancebernstein L.P.	26,030	$292	12/31/2023
MASS	26,030	$292	12/31/2023
Tower Research Capital LLC TRC	25,027	$281	12/31/2023
MASS	25,027	$281	12/31/2023
Millennium Management LLC	24,478	$275	12/31/2023
MASS	24,478	$275	12/31/2023
HRT Financial LP	24,023	$269	12/31/2023
MASS	24,023	$269	12/31/2023
Thrivent Financial for Lutherans	23,470	$263	12/31/2023
MASS	23,470	$263	12/31/2023
UBS Group AG	22,744	$255	12/31/2023
MASS	22,744	$255	12/31/2023
Campbell & CO Investment Adviser LLC	22,224	$249	12/31/2023
MASS	22,224	$249	12/31/2023
Point72 Asset Management L.P.	20,200	$227	12/31/2023
MASS	20,200	$227	12/31/2023
American Century Companies Inc.	19,973	$224	12/31/2023
MASS	19,973	$224	12/31/2023
State of Wisconsin Investment Board	17,834	$200	12/31/2023
MASS	17,834	$200	12/31/2023
Values First Advisors Inc.	17,003	$191	12/31/2023
MASS	17,003	$191	12/31/2023
JPMorgan Chase & Co.	14,542	$163	12/31/2023
MASS	14,542	$163	12/31/2023
Petrus Trust Company LTA	14,009	$157	12/31/2023
MASS	14,009	$157	12/31/2023