(Reuters) -OpenAI said on Wednesday it has not partnered with Robinhood for the stock tokens the trading platform unveiled earlier this week.

Robinhood said on Monday it had launched tokens that would allow its customers in the European Union to get exposure to OpenAI and SpaceX.

"We did not partner with Robinhood, were not involved in this, and do not endorse it," OpenAI said.

The issue highlights a key challenge with tokens linked to private company stock. Privately held startups often have a so-called "right of first refusal", which gives them the first opportunity to buy back their shares before the owner can sell them to an outside party.

Robinhood and SpaceX did not immediately respond to Reuters requests for comment.

(Reporting by Niket Nishant in Bengaluru; Editing by Alan Barona and Shinjini Ganguli)