![Mary Sieghart](data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="%231b1b1b" class="bi bi-person-fill" viewBox="0 0 16 16"><path d="M3 14s-1 0-1-1 1-4 6-4 6 3 6 4-1 1-1 1zm5-6a3 3 0 1 0 0-6 3 3 0 0 0 0 6"/></svg>)
Mary Sieghart
Director/Board Member at
PANTHEON INTERNATIONAL PLC
Net worth: 242 917 $ as of 29/09/2026
Profile
Mary Ann Sieghart currently works at Social Market Foundation, as Chairman from 2010, Pantheon International Plc, as Senior Independent Non-Executive Director, Guardian Media Group Plc, as Senior Independent Director, United Kingdom Office of Communications, as Member-Content Board from 2014, Guardian News & Media Ltd., as Owner, Tate Modern, as Council from 2008, National Association for Gifted Children, as Vice President, The Radcliffe Trust, as Trustee from 2006, Kennedy Memorial Trust, as Trustee, and The Scott Trust (Cheshire), as Trustee.
Ms. Sieghart also formerly worked at Henderson Smaller Cos.
Investment Trust Plc, as Senior Independent Non-Executive Director from 2016 to 2018, The Merchants Trust Plc, as Independent Non-Executive Director from 2014 to 2024, DLN Digital Ltd., as Non-Executive Director, and Times Newspapers Ltd., as Assistant Editor in 2007.
Known holdings in public companies
| Company | Date | Number of shares | Valuation | Valuation date |
|---|---|---|---|---|
| 30/05/2026 | 47,250 ( 0.01% ) | 242 917 $ | 29/09/2026 |
Mary Sieghart active positions
| Companies | Position | Start |
|---|---|---|
| PANTHEON INTERNATIONAL PLC | Director/Board Member | 29/10/2019 |
National Association for Gifted Children
 National Association for Gifted Children Miscellaneous Commercial ServicesCommercial Services Provides support and development of gifted and talented children through education, advocacy, community building and research | Corporate Officer/Principal | 18/10/2010 |
Social Market Foundation
 Social Market Foundation Miscellaneous Commercial ServicesCommercial Services Operates as a non-profit organization to promote evidence based policy and cross party co-operation in politics | Chairman | 31/12/2009 |
The Radcliffe Trust | Director/Board Member | 31/12/2005 |
United Kingdom Office of Communications
 United Kingdom Office of Communications General GovernmentGovernment Provides oversight of the communications industry | Corporate Officer/Principal | 30/06/2014 |
Tate Modern | Corporate Officer/Principal | 31/12/2007 |
Kennedy Memorial Trust | Director/Board Member | - |
The Scott Trust (Cheshire)
 The Scott Trust (Cheshire) Investment Trusts/Mutual FundsMiscellaneous Provides trust services | Director/Board Member | - |
Guardian News & Media Ltd.
 Guardian News & Media Ltd. Publishing: NewspapersConsumer Services Publishes news and news websites | Corporate Officer/Principal | - |
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Former positions of Mary Sieghart
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Experiences
Positions held
Active
Inactive
Listed companies
Private companies
Connections
65
1st degree connections
14
1st degree companies
Male
Female
Members of the board
Executives
Linked companies
| Private companies | 14 |
|---|---|
United Kingdom Office of Communications
United Kingdom Office of Communications General GovernmentGovernment Provides oversight of the communications industry | Government |
Guardian News & Media Ltd.
Guardian News & Media Ltd. Publishing: NewspapersConsumer Services Publishes news and news websites | Consumer Services |
Pantheon International Plc
 Pantheon International Plc Investment ManagersFinance Acts as Private Equity Fund | Finance |
Henderson Smaller Cos. Investment Trust Plc
 Henderson Smaller Cos. Investment Trust Plc Investment Trusts/Mutual FundsMiscellaneous Acts as Closed-End Investment Fund/Investment Trust | Miscellaneous |
The Merchants Trust Plc
 The Merchants Trust Plc Investment Trusts/Mutual FundsMiscellaneous Acts as Closed-End Investment Fund/Investment Trust | Miscellaneous |
Guardian Media Group Plc
 Guardian Media Group Plc Publishing: NewspapersConsumer Services Provides media publishing services | Consumer Services |
Social Market Foundation
Social Market Foundation Miscellaneous Commercial ServicesCommercial Services Operates as a non-profit organization to promote evidence based policy and cross party co-operation in politics | Commercial Services |
Tate Modern | |
Times Newspapers Ltd.
 Times Newspapers Ltd. Publishing: NewspapersConsumer Services Publishes newspaper | Consumer Services |
National Association for Gifted Children
National Association for Gifted Children Miscellaneous Commercial ServicesCommercial Services Provides support and development of gifted and talented children through education, advocacy, community building and research | Commercial Services |
The Radcliffe Trust | |
DLN Digital Ltd.
 DLN Digital Ltd. Movies/EntertainmentConsumer Services Owns, maintains and operates digital equipment | Consumer Services |
Kennedy Memorial Trust | |
The Scott Trust (Cheshire)
The Scott Trust (Cheshire) Investment Trusts/Mutual FundsMiscellaneous Provides trust services | Miscellaneous |
- Stock Market
- Insiders
- Mary Sieghart
