Y Combinator's Tom Blomfield joins Anthropic's compute team

Tom Blomfield, a general partner at Y Combinator and cofounder of the fintech startups Monzo and GoCardless, announced this week that he is taking a leave of absence from the accelerator to join Anthropic.

"Powerful AI has the potential to improve the life of every human on earth and, as we enter the early stages of recursive self-improvement, availability of compute becomes one of the most important issues to solve," he wrote on X.



Blomfield will work on the compute team alongside Anthropic cofounder and chief compute officer Tom Brown. "Excited to work with you again," Brown wrote.

Blomfield was at YC as a partner, mentoring founders across multiple batches after building two unicorns. He was awarded an OBE (Officer of the British Empire) in 2019 for his contribution to competition in banking.

This move comes amid a hiring wave that has reshaped Anthropic's top deck in 2026. Chemistry Nobel laureate John Jumper left Google DeepMind in June to join its science team. OpenAI cofounder Andrej Karpathy joined in May to lead a new pretraining group. Former Microsoft Azure AI president Eric Boyd came aboard to head infrastructure, xAI cofounder Ross Nordeen joined the compute effort, and UC Berkeley CS chair Jelani Nelson signed on as a member of the technical staff in July.

Anthropic has also picked up senior executives across finance, security, and international go-to-market, including former Microsoft India managing director Irina Ghose, who will lead the company's India operations.

The company is scaling rapidly after closing a series G round earlier this year, valuing it at nearly $380 billion. A subsequent raise has pushed that figure towards $965 billion.

Claude Code has become a major enterprise growth driver for the company. But compute is the main bottleneck as Anthropic races to train and serve its next generation of Claude models, the area wherein Blomfield will now work.