The investment bank, in a report issued Thursday, says the metaverse represents a potential $8 trillion to $13 trillion opportunity by 2030, that could boast as many as 5 billion users.

“We believe the Metaverse is the next generation of the internet — combining the physical and digital world in a persistent and immersive manner — and not purely a Virtual Reality world,” the report reads. “A device-agnostic Metaverse accessible via PCs, game consoles, and smartphones could result in a very large ecosystem.”

The 5 billion estimate, the authors concede, is a broad one, that includes a mobile phone user base. If the metaverse is confined to VR/AR devices, it expects the audience to be closer to 1 billion.

Before any of that can occur, though, significant infrastructure investments will be needed, Citi says.

“In the current state, the internet infrastructure is unsuitable for building a fully-immersive content streaming Metaverse environment, that enables users to go seamlessly from one experience to another,” the report reads. “To make the vision of Metaverse a reality, we expect significant investment in a confluence of technology. Low latency — the time it takes a data signal to travel from one point on the internet to another point and then come back — is critical to building a more realistic user experience.”

Finances in the future, it predicts, will be a mix of traditional forms of money and cryptocurrencies, noting that “money in the Metaverse could exist in different forms”.  NFTS will also play a key role, it says, enabling a form of sovereign ownership of digital items for users.

Just as with today’s internet, though, City envisions a split between U.S. and most international users and a China version, which blocks certain content. And consumer hardware manufacturers could be the gatekeepers of the Metaverse.

That could result in legal challenges—something Citi says is a big issue that has not yet been adequately addressed.

“We have a lot to work out,” the report says. “If the Metaverse(s) is the new iteration of the internet, it will attract great scrutiny from global regulators and policymakers. All the challenges of the Web2 internet could be magnified in the Metaverse, including content moderation, free speech, and privacy. In addition, a blockchain-based Metaverse will brush up against still evolving laws around cryptocurrencies and DeFi in many jurisdictions around the world.”

Citi’s not alone in its bullish predictions. Earlier this year, Goldman Sachs’ Eric Sheridan called the metaverse an “$8 trillion market opportunity”.