Nearly 40 Years in Nuclear.
Next: Two Unproven Bets.

On July 10, 2026, Holtec Nuclear Corporation filed its S-1 with the SEC. In one line: it makes money from nuclear’s “cleanup.” Spent nuclear fuel keeps emitting intense radiation and heat, and needs strict, long-term management. Holtec has been building the equipment that stores that spent fuel for about 40 years. Buying retired reactors outright to take them apart is a model it pioneered in the industry in 2018.

On that solid existing business, the company is now making two big bets. One is a new, small reactor it has never operated. The other is a plan to restart a commercial reactor that had permanently shut down and entered decommissioning — the first such effort in the United States. It is pouring the money and credibility earned from cleanup into nuclear’s “next.”

The base is broad. Holtec has delivered to more than 40 countries, and in equipment that stores spent nuclear fuel it holds, by its own account, more than 90% of the U.S. wet-storage market and about 75% of the dry-storage market. Its backlog — work already under contract — runs to roughly $21 billion, much of it stretching from the 2030s into the 2050s.

But the bets are still unsettled. Not a single SMR-300 has been built. And just before the IPO, the company is moving its heavy decommissioning obligations to a separate company owned by the founder’s family. Its 79-year-old founder, using a special class of stock that carries 10 votes per share, will keep control of the company after listing.

Ten questions. We lay out only what the S-1 says.

Question 1

What is this company, really?

A “cleanup” company: it stores nuclear waste and dismantles old reactors.

A reactor is not finished when its fuel is spent. That used fuel keeps emitting intense radiation and heat, and requires strict management for a very long time. So it is first cooled for years in a water pool, then sealed into a rugged steel-and-concrete container for storage.

Making that container is Holtec’s core business. By the company’s own account, it holds more than 90% of the U.S. market for wet (in-pool) storage and about 75% for dry (above-ground) storage. In this field, more than 150 reactors around the world are its customers.

The other pillar is decommissioning — taking reactors apart. In 2018, Holtec pioneered a model of buying a shut-down plant outright and dismantling it itself. As a result, it is now the company that owns the most shut-down reactors in the United States.

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the largest owner of shuttered nuclear reactor units in the United States

HOLTEC S-1 — PROSPECTUS SUMMARY

Dismantling is not quick work. Even after the buildings come down, storing the spent fuel continues for decades. So Holtec’s work keeps arising while a reactor runs, and after it stops.

These two — storing fuel and decommissioning — are the base of a business built over 40 years. It is unglamorous, but as long as reactors exist in the world, the cleanup work will not go away.

While reactors run, and after they stop, the cleanup work does not disappear.

Question 2

What does it compete on?

Two strengths: a leading position in the nuclear back end, and a bet on a new reactor.

A commanding lead in cleanup

Holtec’s strength starts with taking on the whole job at once. From design through materials, manufacturing, and on-site installation, it keeps the main steps in-house. Single-point responsibility gives it greater control over quality, cost, and schedule, and, the S-1 says, lets it capture additional margin.

The other strength is stickiness. The company says that, as of June 30, 2026, no customer had switched away from its dry-storage solution once deployed. Over the past 20 years, 33 reactor units that had used a competitor’s equipment switched to Holtec. Not a single one has moved from Holtec to a competitor.

It also owns materials no one else has. The special neutron-absorbing metals and shielding are made only by Holtec, and are hard for rivals to copy. This is the high wall around the cleanup business.