A Cooler Quarter for UK Series A Investment

The latest VenturePath Venture Bulletin reveals a cooling in UK Series A activity, with both deal value and average round size slipping in Q3.

According to our analysis, Series A deal volumes fell around 9% quarter-on-quarter, while the total amount invested dropped by roughly 15% - equating to £91m less capital deployed into scaling UK companies. The average deal size hit £4.44m, the lowest point this year.

Year-to-date, the picture is flatter: total Series A investment stands at £1.52bn across the first nine months of 2025, just below 2024 levels, despite a slight uptick in deal count.

Meanwhile, mega-deals in AI and deeptech continue to distort the landscape, with two £74m rounds widening the gap between capital-intensive frontier tech and the rest of the market.

These trends underline why The UK ScaleUp Investment Mission remains focused on improving Series A access for the next generation of scaling founders - ensuring the UK continues to convert startup potential into scaleup success.

Read the full Q3 2025 Venture Bulletin for:

• Deeper data on UK Series A deal trends

• Sector insights and quarterly comparisons

• Expert commentary from Sifted’s research team

Read the full Q3 2025 Venture Bulletin for our full report on the UK investment landscape.

Subscribe to the Venture Bulletin to receive quarterly insights on UK venture funding trends.