Amazon’s decision to invest up to $50 billion in OpenAI could hang on whether OpenAI goes public or reaches a loosely defined milestone known as artificial general intelligence, which generally refers to AI that is on par with human abilities, according to three people involved who have communicated with OpenAI executives.

Under the terms of the investment, which are still being negotiated, Amazon would initially invest $15 billion into OpenAI, these people said. The other $35 billion could hinge on OpenAI reaching AGI or going public, the people said. The proposed Amazon investment is part of OpenAI’s current funding round, which could top $100 billion at a valuation of $730 billion before the financing.