However, those in the U.S. cannot access these crypto-inspired tokens due to regulatory restrictions.

“These tokens give retail investors indirect exposure to private markets, opening up access, and are enabled by Robinhood’s ownership stake in a special purpose vehicle,” a Robinhood spokesperson told CNCB in response to the OpenAI post.

A Robinhood spokesperson also told Reuters that a 5 euro giveaway of OpenAI and SpaceX tokens was a “limited” offer enabled by Robinhood’s stake in a special purpose vehicle, without identifying the vehicle.

Elon Musk, the chief executive of SpaceX and Tesla who has long been feuding with OpenAI and its chief executive Sam Altman, posted that OpenAI’s “’equity’ is fake” in response to OpenAI’s warning—a reference to his campaign against its transition from a non-profit to a for-profit business model.

Musk didn’t criticize Robinhood for offering tokenized SpaceX shares, however.

The move by Robinhood and others to “tokenize” stocks and shares is part of a broader push from Wall Street giants and financial technology companies to open up markets using the blockchain technology that underpins bitcoin and other cryptocurrencies.

Earlier this year, Larry Fink, the chief executive of the world’s largest asset manager BlackRock, said he believed “every stock, every bond, every fund, every asset can be tokenized,” writing in annual letter to investors that blockchain-based tokens enabling instant buying, selling, and transfers without paperwork or waiting— “much like a digital deed.”