United Kingdom · 
Who invested in Callosum?
Callosum's investors include Charlie Songhurst, Atomico, DCVC, AlbionVC and Plural, and 1 more on record. Atomico led its latest round.
2027
$10MPre-seed?Venture$100MSeed
United Kingdom · Seed startup
Who invested in Callosum
3 rounds we have observed, with the 6 investors named in them. Every figure came from a named source, and where the company reported a raise to the SEC itself, that is shown beside it.
Raised 3 months ago
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Funding summaryUpdated 5 Nov 2026
$110Mraised across 3 rounds since 2026, from 8 sources
$10MPre-seed$100MSeed
- Latest round
- Seed, $100MAug 2026
- Led by
- Atomico
- Step-upi
- 9.7×
- Investors
- 6 (1 led)
The funding story
Each circle is a round, placed by date and sized by amount. The line above is the running total.
- First round
- Pre-seed, $10M Feb 2026
- Biggest round
- $100M Seed · Aug 2026
- Usual gap between rounds
- 5 months the median of 2
The rounds
- Aug 2026
- Apr 2026
- Feb 2026
Founders and team
From Callosum's own website: 2 founders, 4 on the team.
Danyal AkarcaCo-founder
Jascha AchterbergCo-founder
- James ChalmersHead of Ecosystem and Partnerships
- Ragav ManimaranHead of US
- Benedetta GaggioGeneral Manager
- Natalie WallisOperations Manager
Who was in which round
The busiest backers across the latest rounds. A filled square is a round they joined; a dark one, a round they led.
Everyone who backed them
UK Sovereign AI FundVC firm1round
Missing a round, or an investor who was in one? Tell us.
Also claim to have backed them
These 6 firms list Callosum as a portfolio company on their own websites, but no report of a round names them. They are the firms' own claims, kept apart from the rounds above.
Quick answers about Callosum
How much has Callosum raised?
Callosum has raised $110M across 3 rounds since 2026. One round did not disclose an amount, so the total is a floor.
When did Callosum last raise?
Callosum's most recent round was a Seed of $100M in Aug 2026, led by Atomico.
What was Callosum's biggest round?
Its most recent round, $100M in Aug 2026, is also its largest on record.
Who backed Callosum first?
Callosum's first round on record, in Feb 2026, was backed by Charlie Songhurst.
What stage is Callosum at?
Callosum's latest named round is a Seed, in Aug 2026.
Where is Callosum based?
Callosum is based in the United Kingdom.
Who led Callosum's rounds?
Atomico led the Seed in 2026.
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