Big round · 21 August 2026

Castelion raises $800M Series C led by Andreessen Horowitz

By Millionrounds ResearchPublished 16 September 2026

Castelion, based in United States, has raised $800M in a Series C led by Andreessen Horowitz, JPMorgan Chase's Strategic Investment Group and The Carlyle Group, announced on 21 August 2026. 4 other investors joined. It is the 64th largest equity round we recorded in the twelve months to that date, and the 11th largest Series C of 194. The median Series C over the same period was $100M, so this one is 8.0 times that. Its previous round on record was a Series B of $350M in July 2025, 14 months earlier.

Raised$800M4 sources reported it
StageSeries C2 earlier rounds on record
Investors73 named as lead
Where USUnited States

Defence Tech

How big is it?

Against every equity round we recorded in the twelve months to 21 August 2026. Ranks count companies, so the same raise reported twice is counted once.

#64equity round of the last twelve months
#11Series C of 194 in that time
#41round in United States, of 1,100
This round$800M
Median Series C$100M

8.0 times the median Series C of the last twelve months.

Who invested

Also in the round

Funding history

  1. August 2026Series C$800M
  2. July 2025Series B$350M
  3. January 2025Series A$100M

$1.3B raised across the 3 rounds we hold.

Reported by

  1. TechStartups19 August
  2. TechCrunch20 August
  3. Ventureburn20 August
  4. Crunchbase News21 August

The round's figures come from these reports; each link opens the original.

Other big rounds that week

Starcloud$250M Series AMuon Space$250M Series CCallosum$100M SeedGroq$350M Series AAlso$150M Series DWWispr$280M Series B
The companyCastelion on Millionrounds→Weekly roundupWeek of 17 August→Monthly roundupAugust 2026→