Labor Union

SEIU Local 509




Tax ID:


Tax-Exempt Status:


Budget (2016):

Revenue: $14,099,104
Expenses: $12,231,852
Assets: $5,569,147


Labor Union

Contact InfluenceWatch with suggested edits or tips for additional profiles.

Service Employees International Union (SEIU) 509 is a Massachusetts-based local union of the SEIU, representing about 20,000 educators and human service employees including mental health clinicians, eldercare workers, social workers, early childhood educators, graduate students, and university lecturers. 1

According to its “Solidarity Principles,” the organization is committed to political work both inside and outside the workplace and is thus a strong advocate for left-of-center policies regarding climate change, education, health care, immigration, and critical race theory at both the local and the national levels. 2 The Local self-describes as a “fast growing, progressive union” that aims to “organize and build power.” 3


SEIU Local 509 actively hires external organizers to develop recruitment campaigns and seek out public and private sector workers, introduce them to union organizing, and maintain contacts with them. 4

The union supports a number of left-progressive causes. In 2018, it launched the “SEIU Local 509 Racial Justice Task Force” to work with left-wing racial justice educational and mobilization groups. 5 In July 2020, Local president Peter MacKinnon and Higher Education Chapter president Jaime Wilson released a statement condemning Immigration and Customs Enforcement’s announcement that international students would not be allowed to remain in the U.S. if their schools switched to online-only instruction in Fall 2020, calling the decision “morally reprehensible” and a “calculated move by the Trump Administration” to cause difficulties for the students. 6

In April 2021, the Local released a statement on the conviction of former Minneapolis police officer Derek Chauvin for the second-degree unintentional murder of George Floyd, supporting the verdict but admonishing the U.S. justice system for an overly long and complicated trial despite “countless witnesses, testimony, and camera footage” providing evidence for the fact that Floyd “was murdered in plain sight.” The statement called on the country to “reimagine what the future of policing and public safety look like” and encouraged the labor movement to help “in the fight to dismantle the systems that oppress communities of color.” 7

The union claims to be “committed to fighting for environmental justice” and a “green future” through creating “a green workforce and reducing our carbon footprints.” It argues that “the impact of climate change is shaped by racism and discrimination” since it “disproportionately hurts working people and low-income people.” The Local seeks to integrate “climate justice into the daily work of the union” and mobilize its members to participate in “collective action” for environmental policies. 8

Local 509 maintains a Committee on Political Education (COPE), the SEIU’s political action committee (PAC). It uses money raised by the committee to help pro-SEIU politicians win elections as well as influence the outcome of ballot measures. Local 509 underscores its particular interest in influencing government affairs, noting that many of its members are government workers, and in order to secure them well-paying contracts it needs labor-friendly elected officials. 9


Federal tax returns filed by Local 509 in 2019 showed a total revenue of $14,255,036, total expenses of $13,607,870, and total assets of $8,796,710. 10


Peter MacKinnon is the president of SEIU Local 509. 11 He has served as the union’s president since 2016, when he was promoted from his position as president of the Local’s Department of Children and Families (DCF) chapter. Prior to joining the SEIU, Mackinnon worked in the Massachusetts state government as a supervisor in Child Protective Services. 12


  1. “About Local 509.” SEIU Local 509. Accessed September 9, 2021.
  2. “About Local 509.” SEIU Local 509. Accessed September 9, 2021.
  3. “External Organizers.” SEIU Local 509, May 24, 2021.
  4. “External Organizers.” SEIU Local 509, May 24, 2021.
  5. “Racial Justice.” SEIU Local 509, August 13, 2020.
  6. “SEIU 509 Statement on ICE Rule on Student and Exchange Visitor Program.” SEIU Local 509, June 2, 2021.
  7. “SEIU 509 Statement on the Conviction of Derek Chauvin.” SEIU Local 509, April 20, 2021.
  8. Climate & Environmental Justice Committee.” SEIU Local 509, May 10, 2021.
  9. “COPE.” SEIU Local 509, September 7, 2021.
  10. Service Employees International Union Local 509, Return of Organization Exempt from Income Tax (Form 990), 2019, Part I Lines 12, 18, and 20.
  11. “Who We Are.” SEIU Local 509, December 17, 2020.
  12. LinkedIn. Peter MacKinnon. Accessed September 9, 2021.
  See an error? Let us know!

Nonprofit Information

  • Accounting Period: December - November
  • Tax Exemption Received: November 1, 1943

  • Available Filings

    Period Form Type Total revenue Total functional expenses Total assets (EOY) Total liabilities (EOY) Unrelated business income? Total contributions Program service revenue Investment income Comp. of current officers, directors, etc. Form 990
    2016 Dec Form 990 $14,099,104 $12,231,852 $5,569,147 $1,301,266 N $0 $11,991,291 $31,240 $188,547
    2015 Dec Form 990 $12,143,485 $12,024,829 $3,448,424 $1,047,795 N $0 $11,671,333 $13,281 $181,391 PDF
    2014 Dec Form 990 $11,123,900 $10,775,390 $3,134,684 $852,711 N $0 $10,816,000 $6,755 $173,529 PDF
    2013 Dec Form 990 $9,934,125 $9,779,922 $2,796,483 $863,020 N $0 $9,505,520 $6,538 $295,399 PDF
    2012 Dec Form 990 $9,270,265 $8,988,243 $2,512,238 $732,978 N $0 $8,906,746 $10,482 $127,757 PDF
    2011 Dec Form 990 $8,944,202 $8,550,553 $2,189,739 $697,990 N $0 $8,539,204 $16,027 $228,957 PDF

    Additional Filings (PDFs)

    SEIU Local 509

    MARLBOROUGH, MA 01752-4615