Analysing more than 41,800 UK funding rounds, Antler's Path to Series A report identifies the variables that most strongly predict whether a startup will successfully convert to Series A funding. The findings challenge some widely-held assumptions about what it takes to scale.
The starkest finding concerns SEIS/EIS-only investors: startups that rely solely on tax-efficiency investors convert to Series A at just 3.7%. Add a single institutional co-investor or active angel, and that figure rises to 25.7%.
Crucially, round size alone doesn't guarantee success. Investor quality - measured by conversion track records - is a far stronger predictor. A $1M seed from a reputable VC converts at 43.8%, while companies raising $5M+ from weaker investors showed a 0% conversion rate.
The report defines three non-negotiable factors for founders: crossing the $1M seed threshold, maintaining investor continuity from pre-seed, and raising within the 12–18 month sweet spot after pre-seed.
