Calculus EIS Fund

The first Calculus EIS fund launched in 1999, giving the management team one of the longest track records in the EIS industry. 

Since adopting its current strategy in 2013/14 the Calculus EIS fund has invested £160.4 million into 56 companies. These investments have generated exit proceeds and dividends worth £106.6 million, with a remaining portfolio balance of £112.6 million (October 2023). The fund seeks to invest in companies operating within the technology, healthcare and entertainment sectors. 

  • Target return of 2x over 4-7 years – not guaranteed 
  • Targets a portfolio of at least 6 companies, invested over 12-18 months – not guaranteed 
  • Minimum investment of £25,000 
  • Deadline: 26 July 2024 for next close

Important: The information on this website is for experienced investors. It is not a personal recommendation to invest. If you’re unsure, please seek advice. Investments are for the long term. They are high risk and illiquid and can fall as well as rise in value: you could lose all the money you invest.

The manager

Calculus Capital’s CEO, John Glencross, and Executive Chairman, Susan McDonald, made their first EIS investment in 1996. They founded Calculus Capital in 1999 and shortly after launched the UK’s first approved EIS fund. Calculus now manages £148 million in tax-efficient investments, across its EIS funds and VCT, all managed by the same investment team. 

The investment team is co-led by Alexander Crawford and Richard Moore who are responsible for sourcing and executing new deals, as well as advising portfolio companies. They are supported by a wider team of six, including Dominic Harris, who acts as Head of Portfolio Management and life sciences specialist and Investment Director Elizabeth Klein. 

Before your subscription is invested, the cash will be held by Calculus as the custodian. Calculus also acts as the nominee after investment. 

Investment strategy

The Calculus EIS fund targets revenue-generating companies in the technology, healthcare and entertainment sectors. Investees are expected to show proven products and established business models, managed by an adaptable and experienced management team and with a clear route to exit. 

A large proportion of investments come from Calculus’s investor base and management teams it has successfully backed in the past. Calculus Capital also benefits from its longstanding industry experience and its investment team’s personal networks of lawyers, advisers, and brokers. 

On average, the investment team assesses over 700 deals a year with 1-2% of these making it through the selection process. When reviewing a deal, Calculus conducts its own comprehensive research then brings in external parties for in-depth financial, legal, and commercial due diligence.

Once investments are made, Calculus aims to mitigate risk with a “hands-on” approach. Calculus usually takes a board seat and will monitor performance closely through monthly management accounts. The manager also encourages portfolio companies to adopt strategies aligned with a transition to a more sustainable economy, including reducing energy consumption and promoting high standards of business ethics.

The fund targets and overall return of 2x over four to seven years, not guaranteed. 


The examples outlined below are previous investments made by the Calculus EIS Fund, which has backed 56 companies under its current strategy since 2013/14, but are unlikely to form part of a new investor’s portfolio. They are outlined to give examples of the types of companies an investor might expect.


Founded in 2011, Wazoku is a multi award-winning AI-powered innovation platform used by a wide range of organisations, from NASA, to HSBC, and AstraZeneca.

They can use the platform to connect and interact with their employees, clients, and the rest of the world – to generate fresh ideas, improve collaboration and innovate. An organisation can choose to share “Challenges” with internal teams, select external partners or the Wazoku Crowd, a community of over 100,000 problem solvers spread all over the world. Solvers can be offered financial rewards or partnerships in return for their suggestions.

Calculus first invested in 2019, with the EIS funds investing a total of £3.1 million over multiple rounds. That position is now valued at £9.3 million (October 2023), with other investors including the Octopus Apollo VCT. Past performance is not a guide to future returns.

Optalitix-Calculus-KI-EIS-Fund 2.jpgOptalitix – recent investment

Founded in 2013 by developer and actuary duo Jonathan Shapiro and Dani Katz, Optalitix’s low code software that, in layman's terms, converts spreadsheets into apps.

Designed to automate models in the financial sector, the company’s ‘Models’ product turns existing Excel financial models into cloud-based systems that can be used, monitored and amended across the firm. Its ‘Quote’ product is designed provide a similar service but specifically for underwriting quotes, speeding up the insurance pricing process. The company has secured some large insurance clients, including Vitality, GoCompare and Lloyd’s of London.

Calculus invested £2.5 million, including £1.4 million from the EIS fund, in September 2022. This was part of a £4 million round that also included customer and previous investor United Trust Bank.

Avvio-Calculus-KI-EIS-Fund.jpgAvvio – example of previous exit

Avvio is a business-to-business software-as-as-service (SaaS) company that has developed an AI-powered booking engine for the travel industry, as well as providing digital marketing and web design services. Its technology allows hotels to grow their direct bookings, cutting fees payable to third-party travel agents and improving user experience in the hope of growing repeat customers. 

The company’s booking engine, allora, is used by over 500 hotels around the world, powering £400 million in transactions every year. In the 12 months to March 2022, the company generated revenues of €10.7 million and operating profits of €3.5 million.

Calculus initially invested £3.25 million in the business through the EIS fund in November 2014, building its stake to £3.5 million through follow-on funding. In November 2022, Calculus sold its entire stake to US company SHR – a portfolio company of private equity group Serent Capital which specialises in enterprise software and tech-enabled services - achieving a 5.5x return on its investment. Past performance is not a guide to the future. 

Every1Mobile Limited – example of previous failure 

As is to be expected, not all investments work out. Based in Brighton, Every1Mobile developed a communications platform for inclusion programmes across Africa, creating new communication opportunities for populations that had historically been inaccessible. 

The company worked with clients to create campaigns based on three main themes: health, education, and the ability to earn a living. In one example, the business partnered with Unilever to reach shopkeepers in Africa’s largest slum, Kibera. 

Calculus first invested £2.2 million in November 2017, with subsequent funding taking its total investment to £3.5 million. However, the company struggled following the merger between the Department for International Development and the Foreign and Commonwealth Office, which reduced funding for international projects. As a result, the investment has been written down to nil.


The Calculus EIS fund has invested £160.4 million in 56 companies since adopting its current strategy in 2013/14. There have been 24 exits, of which 11 were profitable with an average exit multiple of 2.8x. Exits proceeds and dividends total £106.5 million, and the remaining portfolio is valued at £112.6 million. Dividends are variable and not guaranteed.

The chart below shows the average performance of the total subscribed into the funds each in each full tax year from 2012/13 (or from when the current strategy was adopted if later) to 2022/23. The chart is based on the latest valuations provided by the manager, expressed on a £100 invested basis. Please note, individual investor portfolios’ performance will deviate from the average. 

Performance of Calculus EIS funds per £100 invested in each tax year

Source: Calculus Capital, as at October 2023. Past performance is not a guide to future performance. The chart shows realised returns, if any (where share proceeds have been returned to investors as cash) and unrealised returns (where cash has not yet been returned and the value of the investments is based on the manager’s own valuation methodology). There is no ready market for unlisted shares. The figures shown are net of all fees and do not include any income tax relief or loss relief.

Risks – important

This, like all investments available through Wealth Club, is only for experienced investors happy to make their own investment decisions without advice. 

EIS investments are high-risk and should only form part of a balanced portfolio. As must be expected with early-stage investments, some or even all of the companies in the portfolio could fail: the fewer the companies included in the portfolio, the higher the risk of loss if things don’t go to plan. You should not invest money you cannot afford to lose.

There is no ready market for unlisted EIS shares: they are illiquid and hard to sell and value. There will need to be an “exit” for you to receive a realised return on your investment. Exits are likely to take considerably longer than the three-year minimum EIS holding period; equally, an exit within three years could impact tax relief.

To claim tax relief, you will need EIS3 certificates, normally issued once shares have been allotted. This can take several months: please check the deployment timescales carefully. Tax reliefs depend on the portfolio companies maintaining their EIS-qualifying status. Remember, tax rules can change and benefits depend on circumstances.

Before you invest, please carefully read the Risks and Commitments and the offer documents to ensure you fully understand the risks. 

Calculus Capital has an exclusive focus on EIS and VCT investments, both of which are subject to HMRC rules which can change frequently. This could leave the firm and its investee companies vulnerable if rules change unfavourably.


A summary of the main charges and savings is shown below. Some of these will be payable by the investor, whilst others by the investee companies. The investment may have additional charges and expenses: please see the provider documents, including the Key Information Document, for more details.

The initial charge consists of a 2% transaction fee and a non-advised investor set-up fee of 1%.

Investor charges
Full initial charge 3%
Wealth Club initial saving
Net initial charge through Wealth Club 3%
Annual management charge 2%
Administration charge
Dealing charge 0.65%
Performance fee 10%
Investee company charges
Initial charge Variable
Annual charges Variable
The fees and charges above are stated exclusive of VAT, which applies in some cases, as determined by the manager. Please check the VAT position carefully in the provider documents. Any fees and charges payable by the investee companies or the underlying businesses do not directly come out of your investment. However, they will effectively reduce the returns generated by investee companies and therefore impact your investment.

More detail on the charges

Our view

Calculus is one of the longest-standing EIS fund managers. The fund follows an investment strategy that has been well rehearsed within the existing Calculus EIS fund and VCT. 

Calculus’ established market position has helped the team raise and deploy a sizeable amount of capital in the last 20 years. Many of those investments have been successfully exited, resulting in a stream of realised returns – past performance is not a guide to the future.

Wealth Club aims to make it easier for experienced investors to find information on – and apply for – investments. You should base your investment decision on the offer documents and ensure you have read and fully understand them before investing. The information on this webpage is a marketing communication. It is not advice or a personal or research recommendation to buy any of the investments mentioned, nor does it include any opinion as to the present or future value or price of these investments. It does not satisfy legal requirements promoting investment research independence and is thus not subject to prohibitions on dealing ahead of its dissemination. 

The details

Target return
Funds raised / sought
Minimum investment
26 Jul 2024
Last updated: 2 November 2023

News about EIS Investments. Read all