Tax Manager

About the role

Mainspring Energy is a company that designs and delivers fuel-flexible, low-emission local power solutions that add capacity quickly and provide reliable, affordable, and sustainable electric power. The company began commercial shipments of its Mainspring Linear Generators in 2020 and currently oversees 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 role of Tax Manager is critical for building the tax function and establishing robust processes as the company scales. You will move beyond simply processing returns to become a true business operator and internal owner of key compliance and risk activities. This position provides meaningful ownership, broad exposure across the business, and direct visibility with senior leadership. It is ideal for a technically strong tax professional who enjoys creating structure, improving processes, and taking on significant responsibility in a rapidly growing clean energy environment.

Key facts

What you'll do

Drive federal and state income tax compliance by owning the end-to-end processes, including coordination with external tax advisors and ensuring timely filings.

Lead the quarterly and annual ASC 740 tax provision processes, maintaining accurate calculations, documentation, and disclosures in a timely manner.

Maintain comprehensive tax calendars, filing schedules, and payment obligations across all operating jurisdictions to ensure strict adherence to deadlines.

Support audits, tax notices, and inquiries from federal and state authorities by gathering documentation, preparing responses, and managing communications.

Monitor tax law changes at the federal, state, and local levels and assess the potential business impacts on operations, cash flow, and compliance.

Lead multi-state sales and use tax compliance initiatives, including conducting nexus analysis, managing registrations, and ensuring proper tax collection.

Manage sales tax audits, exemptions, and documentation requirements to maintain compliance and minimize potential liabilities.

Oversee business personal property tax filings and related compliance activities across jurisdictions to ensure accurate reporting and payments.

Partner with Finance, Legal, Operations, Sales, and FP&A to ensure accurate tax treatment of transactions, contracts, and capital assets.

Help manage Mainspring's corporate insurance programs, including broker relationships, renewals, coverage reviews, and claims management activities.

Support contract insurance reviews and claims management activities to protect company interests and ensure appropriate coverage.

Partner with Legal and Operations to identify, assess, and mitigate emerging business risks related to tax, insurance, and regulatory compliance.

Build, document, and maintain scalable tax processes and internal controls that support efficient operations and clear accountability.

Evaluate and implement tax automation tools where appropriate to improve accuracy, reduce manual effort, and support scalable operations.

Bring tax activities in-house where it creates efficiency, better business visibility, and long-term process improvements.

Help establish the foundation for a larger, more sophisticated tax and risk management function as the company continues to grow.

Requirements

Bring a minimum of 5+ years of progressive tax experience gained in public accounting, industry, or a combination of both to this role.

Demonstrate strong knowledge of ASC 740 income tax accounting and the full tax provision process, including recognition, measurement, and disclosure requirements.

Show hands-on experience with federal and state income tax compliance, including filing preparation, payment coordination, and response to official inquiries.

Possess practical experience with multi-state sales and use tax compliance, including conducting nexus analysis, managing registrations, and resolving audit matters.

Show familiarity with property tax compliance in multiple jurisdictions, including assessment appeals, filings, and interactions with local tax authorities.

Prove the ability to manage multiple deadlines and priorities independently while maintaining a high standard of accuracy and attention to detail.

Communicate complex tax concepts clearly and effectively to both tax professionals and non-tax stakeholders across the organization.

Work effectively with non-tax stakeholders such as Finance, Legal, Operations, Sales, and FP&A to support cross-functional initiatives and compliance efforts.

Nice to have

Seek candidates with Big 4 or regional public accounting experience who understand the demands of high-quality tax compliance and advisory work.

Value experience supporting manufacturing, industrial, energy, hardware, or capital equipment businesses because it aligns with Mainspring's operating model.

Look for exposure to energy tax incentives, R&D tax credits, or other business tax credits that can optimize tax positions and create financial benefits.

Have experience with tax technology platforms such as Avalara, Vertex, OneSource, or CorpTax to streamline compliance and improve process efficiency.

Bring exposure to IPO readiness, public company reporting, or SOX environments where strict controls and timely delivery are essential.

Show familiarity with corporate insurance programs and risk management activities to support broader enterprise risk initiatives.

Practical notes

This is a salary-based position located in Menlo Park, California. The role requires travel as needed for audits, meetings with tax advisors, and business operations support. Candidates must be eligible to work in the United States without sponsorship at this time.