There's a catch in OpenAI's $6.6 billion funding deal that no one is talking about

Andrew Caballero-Reynolds/AFP/Getty Images

• There's an important stipulation on OpenAI's historic $6.6 billion funding round.
• The startup has two years to become for-profit, or it might have to give investors their money back.
• The process is likely to be complicated and could involve a battle in court, legal experts said.

OpenAI's historically large $6.6 billion funding round is bringing in checks from some of the biggest technology and venture capital investors.