Sora was unveiled in 2024 to huge interest around the world due to the high quality of its AI-generated videos.
But there were questions around how much money could be made from the tool.
Since the platform's launch, Sora made $1.4m in global net in-app revenues, compared to $1.9bn over the same period for ChatGPT, according to data from Seema Shah, VP of insights at market intelligence firm Sensor Tower.
Forrester analyst Thomas Husson told BBC News it was "a resource black hole" with "limited monetisation".
"The platform struggled to prevent the creation of non-consensual imagery and realistic misinformation, not to mention major copyright infringement," he said.
Husson said the decision may have been taken now to "minimise the associated risks" in the run-up to a potential stock launch, which would turn OpenAI into a public company where shares could be bought and sold on an open market.
"Given OpenAI is still unprofitable and pressure from investors and rivals is growing, this is cash they likely decided they can't afford to continue burning as initial interest has faded," said Henry Ajder, an expert on AI and deepfakes.