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MASS SCHEDULE 13G/A: SEC filing

ARK Investment Management LLC and Catherine D. Wood

Filed with the SEC on · accession 0001104659-26-096944

MASS filed a SCHEDULE 13G/A (schedule 13g/a) with the SEC on Aug 14, 2026. ARK Investment Management LLC and Catherine D. The stock moved -1.0% by the first close after the filing.

Summary of the filing

ARK Investment Management LLC and Catherine D. Wood filed Amendment No. 9 to their Schedule 13G regarding their ownership of 908 Devices Inc. common stock, executed as a joint filing agreement.

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Key details

Filer / beneficial ownerARK Investment Management LLC
Issuer908 Devices Inc.
Chief executive officer, chief investment officer of ark investment management llcCatherine D. Wood
Chief compliance officer of ark investment management llcKellen Carter

How MASS stock reacted

Close before

$10.11

Aug 13, 2026

First close after

-0.99%

$10.01

5 trading days

+2.37%

$10.35

Since filing

+4.45%

$10.56

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Frequently asked questions

What did MASS file with the SEC on Aug 14, 2026?

MASS filed a SCHEDULE 13G/A (SEC filing). ARK Investment Management LLC and Catherine D. Wood filed Amendment No. 9 to their Schedule 13G regarding their ownership of 908 Devices Inc. common stock, executed as a joint filing agreement.

How do I read a SCHEDULE 13G/A?

A report the company filed with the SEC (the US market regulator). Start with the summary, then the key amounts and names. Compare it with the company’s earlier filings.

Why are SEC filings important?

Public companies must tell the SEC about anything that can change their value — results, leadership changes, big deals, new shares, bankruptcy. Filings are the official source, often before the news. A SCHEDULE 13G/A (schedule 13g/a): A report the company filed with the SEC (the US market regulator).

How did MASS stock react to this filing?

MASS closed at $10.11 before the filing and $10.01 on Aug 14, 2026 (-0.99%). Five trading days later: $10.35 (+2.37%).

Other MASS SEC filings

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