Arthur Glencross
Net worth: 54 921 $ as of 31/07/2026
Net worth: 54 921 $ as of 31/07/2026
John co-founded Calculus with Susan McDonald in 1999, creating one of the UK’s most successful, independent venture capital and private equity firms focused on investing in growth companies.
John has invested in, advised on, or negotiated more than 100 transactions and served on publicly quoted and private corporate boards.
He is a director of several of the companies which Calculus has invested in.
Before co-founding Calculus, John served as a European Corporate Finance Director at UBS, and, prior to this he was Head of Mergers and Acquisitions at Phillips and Drew, a 100-year-old London-based financial institution.
At the start of his career, John qualified as a Chartered Accountant with Peat Marwick (subsequently KPMG), John has an MA from Oxford University in Philosophy, Politics and Economics.
| Company | Date | Number of shares | Valuation | Valuation date |
|---|---|---|---|---|
CALCULUS VCT PLC 0.08% | 31/03/2025 | 76,640 ( 0.08% ) | 54 921 $ | 31/07/2026 |
| Companies | Position | Start |
|---|---|---|
| CALCULUS VCT PLC | Director/Board Member | 10/02/2010 |
Calculus Capital Ltd.
Calculus Capital Ltd. Investment ManagersFinance Calculus Capital invests in small and medium sized companies located in the United Kingdom. The firm focuses on technology, healthcare and creative industries. It participates in early and growth capital requirements with an investment size ranging from GBP 1 to GBP 3 million. It takes board seat and also makes co-investments. | Chief Executive Officer | 01/11/1999 |
Enterprise Investment Scheme Association
Enterprise Investment Scheme Association The Enterprise Investment Scheme Association (EISA) is the official trade body representing over 400 members—including entrepreneurs, investors, advisers, fund managers, lawyers, accountants, and wealth managers—engaged with the Enterprise Investment Scheme (EIS) and Seed Enterprise Investment Scheme (SEIS). These government-backed schemes provide tax incentives to encourage private investment in early-stage and high-growth UK companies, offering income tax relief, capital gains tax exemptions, and loss relief. The private company is based in London, UK. EISA supports its membership through tailored categories, resources such as a knowledge hub, member directory, policy updates, accreditation courses, events, and networking opportunities. The association advocates for the schemes by engaging with government and regulators, promotes professional and ethical standards, and fosters diversity initiatives. EISA emphasizes the importance of understanding the long-term, illiquid, and higher-risk nature of EIS/SEIS investments and encourages members to seek independent advice. | Director/Board Member | - |
Raindog Films Ltd.
Raindog Films Ltd. Movies/EntertainmentConsumer Services Provides motion picture production services | Director/Board Member | 14/06/2022 |
Brouhaha Entertainment Ltd.
Brouhaha Entertainment Ltd. Movies/EntertainmentConsumer Services Engages in production of motion pictures | Director/Board Member | 01/06/2022 |
Wonderhood Ltd.
Wonderhood Ltd. Movies/EntertainmentConsumer Services Provides video production services | Director/Board Member | 01/11/2021 |
Maven Screen Media Ltd.
Maven Screen Media Ltd. Movies/EntertainmentConsumer Services Operates as a media and entertainment development, production and advisory company | Director/Board Member | 11/08/2020 |
Riff Raff Entertainment Ltd.
Riff Raff Entertainment Ltd. Movies/EntertainmentConsumer Services Provides film and television production services | Director/Board Member | 14/06/2022 |
| Companies | Position | End |
|---|---|---|
Terrain Energy Ltd.
Terrain Energy Ltd. Contract DrillingIndustrial Services Engages in oil and gas exploration and production services | Director/Board Member | 03/02/2020 |
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Active
Inactive
Listed companies
Private companies
1st degree connections
1st degree companies
Male
Female
Members of the board
Executives
| Private companies | 14 |
|---|---|
Neptune-Calculus Income & Growth VCT Plc
Neptune-Calculus Income & Growth VCT Plc Investment ManagersFinance Acts as Private Equity Fund | Finance |
Calculus VCT PLC
Calculus VCT PLC Investment ManagersFinance Acts as Private Equity Fund | Finance |
University of Oxford
University of Oxford Other Consumer ServicesConsumer Services Functions as a College/University | Consumer Services |
UBS AG (London Branch)
UBS AG (London Branch) Investment Banks/BrokersFinance Provides brokerage services | Finance |
Calculus Capital Ltd.
Calculus Capital Ltd. Investment ManagersFinance Calculus Capital invests in small and medium sized companies located in the United Kingdom. The firm focuses on technology, healthcare and creative industries. It participates in early and growth capital requirements with an investment size ranging from GBP 1 to GBP 3 million. It takes board seat and also makes co-investments. | Finance |
Terrain Energy Ltd.
Terrain Energy Ltd. Contract DrillingIndustrial Services Engages in oil and gas exploration and production services | Industrial Services |
Lime Technology Ltd.
Lime Technology Ltd. Wholesale DistributorsDistribution Services Develops lime based building products | Distribution Services |
Human Race Group Ltd.
Human Race Group Ltd. Casinos/GamingConsumer Services Owns and operates mass participation sports | Consumer Services |
Enterprise Investment Scheme Association
Enterprise Investment Scheme Association The Enterprise Investment Scheme Association (EISA) is the official trade body representing over 400 members—including entrepreneurs, investors, advisers, fund managers, lawyers, accountants, and wealth managers—engaged with the Enterprise Investment Scheme (EIS) and Seed Enterprise Investment Scheme (SEIS). These government-backed schemes provide tax incentives to encourage private investment in early-stage and high-growth UK companies, offering income tax relief, capital gains tax exemptions, and loss relief. The private company is based in London, UK. EISA supports its membership through tailored categories, resources such as a knowledge hub, member directory, policy updates, accreditation courses, events, and networking opportunities. The association advocates for the schemes by engaging with government and regulators, promotes professional and ethical standards, and fosters diversity initiatives. EISA emphasizes the importance of understanding the long-term, illiquid, and higher-risk nature of EIS/SEIS investments and encourages members to seek independent advice. | |
Wonderhood Ltd.
Wonderhood Ltd. Movies/EntertainmentConsumer Services Provides video production services | Consumer Services |
Raindog Films Ltd.
Raindog Films Ltd. Movies/EntertainmentConsumer Services Provides motion picture production services | Consumer Services |
Maven Screen Media Ltd.
Maven Screen Media Ltd. Movies/EntertainmentConsumer Services Operates as a media and entertainment development, production and advisory company | Consumer Services |
Brouhaha Entertainment Ltd.
Brouhaha Entertainment Ltd. Movies/EntertainmentConsumer Services Engages in production of motion pictures | Consumer Services |
Riff Raff Entertainment Ltd.
Riff Raff Entertainment Ltd. Movies/EntertainmentConsumer Services Provides film and television production services | Consumer Services |
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