Legal artificial intelligence platform Harvey secured $550 million in new funding on Wednesday, driving its valuation to $15.5 billion.

Co-led by venture capital firms Diffusion and Lightspeed Venture Partners, the transaction pushes Harvey’s total raised capital past $1.55 billion. The investment nearly doubles the company’s valuation over a nine-month period, following an $11 billion valuation in March and an $8 billion valuation in December.

The company chose not to formally name the funding round. According to estimates from PitchBook, Harvey has completed at least eight priced rounds since 2023, including five since 2025. Given previous extension rounds, this latest capital injection effectively functions as a Series F.

The influx of capital follows the recent launch of Harvey Tenet, the company’s first proprietary in-house model. Built using the open-weight Kimi K3 foundation and post-trained on specialized legal data alongside inference provider Fireworks, the tool highlights a shift away from standard proprietary systems.

Beyond deploying its own system, Harvey is actively urging clients across the legal sector to adopt and post-train open-weight architectures tailored to their specific needs.

Key developments driving Harvey’s momentum include:

• Expanding Financial Capital: Over $1.55 billion in total funding secured across eight priced rounds since 2023.
• Rapid Valuation Growth: Progression from $8 billion in December to $11 billion in March, reaching $15.5 billion in the latest round.
• Custom Model Infrastructure: Partnership with Fireworks to train Harvey Tenet, mirroring training approaches used by developers like Cursor.
• Industry Independence: A framework enabling law firms to deploy tailored AI models without relying exclusively on frontier labs like OpenAI and Anthropic.