Tax Manager

Job Description

Job Description

About Mainspring

Mainspring Energy manufactures and delivers fuel-flexible, low-emissions local power solutions that rapidly add new capacity and deliver reliable, affordable, and sustainable electric power. The company began commercial shipments of its Mainspring Linear Generators in 2020 and today has hundreds of megawatts in advanced development and field operations for leading Fortune 500 companies, data centers, and utilities. Mainspring also partners with global energy leaders including AEP, NextEra Energy Resources, Schneider Electric, and more.

The core values that ground our work, guide our decisions, and connect us together:

• Pragmatic Optimism
• Excellence without Ego
• Proactive Collaboration

As Mainspring continues to scale, we are looking for a Tax Manager who wants to move beyond processing returns and become a true business operator. Reporting to the VP of Finance & Corporate Controller, you will build and own key tax and risk management processes that support the company’s next stage of growth.

Rather than stepping into a mature tax department, you will have the opportunity to help build one. This role offers meaningful ownership, broad exposure across the business, and direct visibility with senior leadership. You will influence how Mainspring approaches tax compliance, risk management, automation, and scalability while developing the skills needed to grow into future management and leadership opportunities.

This role is ideal for a technically strong tax professional who enjoys creating structure, improving processes, and taking ownership. You will partner across Finance, Legal, Operations, Sales, and FP&A while serving as Mainspring’s internal resource on tax compliance, tax reporting, and corporate insurance matters.

If you are a builder who enjoys combining technical expertise with operational impact, this is an opportunity to make a lasting mark on a rapidly growing clean energy company.

• Own federal and state income tax compliance activities and coordinate with external tax advisors

• Manage quarterly and annual ASC 740 tax provision processes

• Maintain tax calendars, filing schedules, and payment obligations across jurisdictions

• Support audits, tax notices, and inquiries from federal and state authorities

• Monitor tax law changes and assess business impacts

• Lead multi-state sales and use tax compliance, including nexus analysis and registrations

• Manage sales tax audits, exemptions, and documentation requirements

• Oversee business personal property tax filings and related compliance activities

• Partner with internal stakeholders to ensure accurate tax treatment of transactions and assets

• Help manage Mainspring’s corporate insurance programs, including renewals, broker relationships, and coverage reviews

• Support contract insurance reviews and claims management activities

• Partner with Legal and Operations to identify and mitigate emerging business risks

• Build and document scalable tax processes and controls

• Evaluate and implement tax automation tools where appropriate

• Bring tax activities in-house where it creates efficiency and better business visibility

• Help establish the foundation for a larger, more sophisticated tax and risk management function

• 5+ years of progressive tax experience in public accounting, industry, or a combination of both

• Strong knowledge of ASC 740 income tax accounting and tax provision processes

• Experience with federal and state income tax compliance

• Hands-on experience with multi-state sales and use tax compliance and nexus analysis

• Familiarity with property tax compliance in multiple jurisdictions

• Ability to manage multiple deadlines and priorities independently

• Strong communication skills and ability to work effectively with non-tax stakeholders

• Big 4 or regional public accounting experience

• Experience supporting manufacturing, industrial, energy, hardware, or capital equipment businesses

• Exposure to energy tax incentives, R&D tax credits, or other business tax credits

• Experience with tax technology platforms such as Avalara, Vertex, OneSource, or CorpTax

• Exposure to IPO readiness, public company reporting, or SOX environments

• Familiarity with corporate insurance programs and risk management activities

This position is onsite at our Menlo Park HQ . The salary will be adjusted to reflect local market conditions based on employee location as well as the experience of the employee. Along with the base salary, Mainspring offers stock options + benefits.

Does your experience not meet all of our posted requirements? Studies have shown that some people are less likely to apply to positions unless they meet every listed requirement. At Mainspring, we are committed to building a diverse, inclusive, flexible, and collaborative environment, so if you want to help us transition the world to clean and affordable electricity, and don’t meet all posted requirements for a particular role, we’d still love to hear from you. Mainspring can sometimes be flexible enough to shift responsibilities for the right person, or otherwise identify open or upcoming roles that may better fit your professional background.

In more traditional words, Mainspring Energy, Inc is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, or protected veteran status and will not be discriminated against on the basis of disability.

This compensation and benefits information is based on Mainspring Energy's estimate as of the date of publication and may be modified in the future. We generally do not negotiate on salary once we have made an offer. The level of pay within the range will depend on a variety of job-related factors that may include location, relevant prior experience and/or education, or particular skills and expertise. New hires joining the company tend to be paid within the starting base pay range noted above, with opportunities to increase pay over time based on development of additional skills, competencies, and company-specific knowledge.

We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses and identifying potential inconsistencies or verification signals in application materials based on available information. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us.