Growth Tax Manager - Onside Tax

Reporting to: Head of Tax - Onside Tax

Salary: £45,000 to £60,000 depending on experience and qualifications

Location: Remote - working from home in the UK

The UK tech sector is growing rapidly and becoming an increasingly important part of the economy. At Onside, we’ve built a genuinely differentiated way to support tech-led businesses, combining premium client service with modern systems, automation and commercial thinking.

We believe the strongest professional services firms of the future will be technology-led by design, with automation and data removing low-value work so people can focus on judgement, relationships and impact. Onside is being built deliberately around that belief. We are not just users of technology; we are, in part, a technology company ourselves, backed by Multiplier, a San Francisco–based, AI-native professional services company designed to transform our industry.

The Tax Manager will take ownership of Onside’s wider tax offering for fast-growing, VC-backed technology businesses, acting as a trusted lead on day-to-day delivery while working closely with the Head of Tax and Managing Director. The role centres on transfer pricing, EMI, EIS/SEIS, VAT and other tax matters that arise as clients grow, and is well suited to someone who works well with autonomy, enjoys responsibility, builds strong client relationships and thrives in a fast-paced, tech-led environment.

This is a fast paced role with high standards. We value accuracy, curiosity and ownership and there is a clear progression path for people who demonstrate energy and capability. It’s an opportunity to learn how modern, technology led finance teams really operate and build a strong platform for your continued career.

Applicants must be confident managing priorities, delivering work independently and collaborating effectively in a remote environment, including throughout their initial training and induction period.

This role requires substantial experience of long-term homeworking within a UK accounting practice. Remote working experience gained solely during Covid-19 restrictions will not be considered. Applicants from formal hybrid arrangements may be considered, provided homeworking was a long-term, contracted arrangement involving typically two to three days per week working from home.

Key Responsibilities

The key responsibilities of the Tax Manager are:

Taking ownership of a portfolio of tax work for start-up and scale-up clients, and acting as a key point of contact on the matters they lead.

Preparing and delivering tax advice on transfer pricing matters, including scoping, technical analysis, report writing and implementation support.

Preparing EMI valuation reports and supporting clients with EMI and ERS advice/compliance, including HMRC submissions and related advisory work.

Preparing EIS1/SEIS1 compliance filings and supporting advance assurance applications.

Advising clients on VAT matters, including UK and cross-border issues arising as businesses grow and expand into other jurisdictions.

Supporting clients with ad hoc tax advisory projects, including restructurings, remuneration planning, employment-related tax issues and wider corporate tax matters.

Reviewing Corporation Tax returns and associated computations on an ad hoc basis, working alongside the accounts team who manage preparation, and providing technical input to ensure accuracy and identify risks or planning opportunities.

Undertaking tax research, reviewing legislation and HMRC guidance, and forming well-reasoned conclusions based on independent analysis.

Producing high-quality written advice, reports and technical correspondence for clients and internal use.

Leading and contributing to client calls and meetings, explaining technical tax issues in a clear, practical and commercial way.

Building strong client relationships, supporting efficient delivery, and identifying improvements in processes, technology, automation and wider commercial opportunities across the tax function.

Personal and Continued Professional Development

You will be ACA/ACCA qualified or equivalent, and you will undertake, achieve and maintain the mandatory level of informal and formal training required to meet the company’s expectations in terms of service standards, client service, quality and performance.

Additionally, you are expected to:

Display strong ownership of outcomes, consistently exceeding performance expectations.

Participate in training and support delivered by other Onside employees or external service providers.

Take responsibility for own professional development, learning and performance and demonstrate skills and activities to others who are undertaking similar work.

In support of your continued personal and professional development, you will:

Participate in an annual Performance Appraisal to review the individual’s performance against agreed targets.

Take responsibility for maintaining and updating their own personal and/or professional development, learning, performance and skills to support colleagues, clients, raise standards of service, and improve the performance of the wider team.

In conjunction with your Line Manager, ensure that your performance is discussed and
aligned to company’s expectations and objectives.

Confidentiality

In the performance of the duties outlined in this job description, you may have access to confidential information relating to client companies, their directors and employees and their financial position. You may also have access to information relating to the company as a business organisation. All such information from any source is to be regarded and managed as strictly confidential.

You will be expected and required to undertake and complete any other duties as deemed relevant to position and the business needs of the company.

This job description will be subject to periodic review and amendment in consultation with the post-holder(s).

Personal Specification

ATT and/or CTA qualified, or fully qualified ACA, CA, ACCA or equivalent.

5+ years’ experience in a UK practice-based tax role, including 3+ years’ post-qualification experience. Strong experience in some or all of transfer pricing, EMI/share schemes, EIS/SEIS, VAT, and wider corporate tax compliance and advisory work. Experience of owning a defined portfolio of tax work and managing multiple deadlines in a fast-paced environment.

Strong client-facing experience, with the confidence to work directly with founders, senior stakeholders and finance teams. Strong technical tax capability, including legislative and case law research, HMRC guidance review, tax analysis and report writing.

Experience working with a high degree of autonomy and accountability in a remote environment. Extensive structured home-working experience beyond temporary Covid arrangements. Strong IT skills and the ability to adapt quickly to new systems, software and processes.

A strong interest in working with fast-growing technology start-ups and scale-ups.

Residency & Visa Status

You must be resident in and have a legal right to work in the UK.

This is a home-working role with all staff at Onside working from home across in the UK.