OpenAI, an artificial intelligence start-up, has raised a record-breaking $40 billion in funding.The funding round, led by SoftBank and Microsoft, values OpenAI at $300 billion, making it one of the world's most valuable private companies.The company plans to use the funds to further advance AI research and scale its compute infrastructure.OpenAI's ChatGPT has seen exponential growth, with 500 million weekly users and an expected revenue of $12.70 billion by 2025.