CHALLENGE

Seed-stage finance wasn’t built for a public-market sprint.

The company's first finance setup did its job in the early days. Growth changed the requirement. Deep Fission needed faster closes, reporting it could rely on, sharper planning, and records that would hold up to investors, auditors, and regulators.

Then, the timeline moved. In August 2025, the U.S. Department of Energy selected Deep Fission as one of 11 projects in its Reactor Pilot Program. By the company's own account, that milestone pulled its commercialization plan forward by years and turned capital-market access into a near-term priority.

There was no time to upgrade one function at a time. Deep Fission needed senior people who could take on accounting, payroll, financial planning, and transaction readiness at once, without slowing the engineering work.

SOLUTION

Why Finvisor

The introduction came through a former Finvisor client who recommended the team without reservation. The fit was practical: one partner could run the whole back office, quickly bring in senior expertise, and scale support up or down as the plan changed.

Finvisor rebuilt the back office while preparing the raise.

Finvisor embedded a fractional CFO, controller, and accounting specialists in Deep Fission's day-to-day operations. Rather than run each fix as its own project, the team worked across four tracks at once.

A close that runs on schedule.

Senior accountants cleaned up the books, tightened recurring workflows, and cut the monthly close from 20 days to 5. Payroll and finance operations were rebuilt alongside accounting, so the two grew on the same footing.

A model leadership can plan against.

Finvisor re-cut the financial model and cap table, giving leadership a clear read on cash, scenarios, and financing needs as the timeline shifted.

Books ready for the transaction.

The Finvisor team formed a special purpose vehicle (SPV) to aggregate investors ahead of the raise. Audit-ready financials followed, along with the reporting the reverse merger and public-company transition required.

A handoff that kept the context.

When Deep Fission hired an in-house CFO and controller, Finvisor worked alongside them through a staged handoff. Nothing about how the numbers got there walked out the door.

"Finvisor's work in establishing efficient processes and delivering high-quality financials was instrumental in helping Deep Fission pass the audit required to list publicly on an aggressive timeline."

- W Mark Schmitz, Chief Financial Officer, Deep Fission

RESULTS

From seed-stage systems to public-company operations.

With the back office in shape, Deep Fission moved the moment its capital-market window opened. The reverse merger closed September 5, 2025, alongside a $30M private placement. Another $80M followed in February 2026, then a $40M public offering and a Nasdaq debut in June 2026.

The three financings brought in $150M in gross proceeds and brought Deep Fission’s total funding to $160M. Just as important, the company went into that stretch with a 5-day close, a current model and cap table, audit-ready financials, and people ready for SEC reporting.

• 20 to 5 days

  Monthly close time, a 75% reduction

• September 2025

  $30M private placement and completed go-public reverse merger

• February 2026

  $80M private financing

• June 2026

  $40M public offering and Nasdaq trading under FISN

WHERE ARE THEY NOW

Built for the stage that comes next.

Deep Fission now runs day-to-day finance with an in-house CFO and controller. Finvisor supported the transition, handed over the operating history behind the numbers, and continues to support questions and special projects.

The takeaway outlasts the transaction. Finance infrastructure built early is what a company draws on when its timeline jumps. Deep Fission never had to stop and fix the basics when the opportunity arrived. The groundwork was already in place.