Billionaire hedge fund legend Ray Dalio says he holds only a "small percentage" of Bitcoin.

He said that bitcoin will faces major structural hurdles before it can realistically compete as a global reserve currency.

On Nov. 20, the Bridgewater Associates founder reiterated long-standing concerns about Bitcoin's long-term vulnerabilities, despite acknowledging that he continues to keep a small allocation.

"I have a small percentage of Bitcoin… I've had it forever, like 1% of my portfolios," Dalio said on CNBC's  Squawk Box.

Bitcoin was down below $90,000 earlier this week after the United States government failed to release October jobs data, a macro shock that heightened uncertainty across risk assets and tech equities.

Related: What is Crypto? Cryptocurrency explained

Dalio says Bitcoin cannot function as a reserve asset 

Dalio, regarded as one of the most influential macro investors of the past half-century, argued that Bitcoin's transparency and technical constraints make it unsuitable as the foundation of global monetary reserves.

"It's not going to be a reserve currency for major countries because it can be tracked," he said.

He also issued a renewed warning about Bitcoin's long-term security in a world shaped by accelerating computing power, including quantum computing.

"It could be conceivably, with quantum computing, controlled, hacked, and so on and so forth."

Chainalysis, a blockchain analytics firm, estimates that accelerating advances in quantum computing could crack Bitcoin's underlying cryptography within the next 10–15 years, posing a long-term threat to the network's security.

• Future quantum computers could crack Bitcoin's underlying encryption.

• Hackers may save public keys now and unlock them later once quantum tech matures.

• Experts warn this could be possible within the next 10–15 years. 

Related: New warning says quantum tech may crack Bitcoin by 2040

Bridgewater Associates's Dalio has a cautious stance on Bitcoin

Dalio is the billionaire founder of Bridgewater Associates, the world's largest hedge fund, and one of the most influential macro investors of the past five decades. 

Dalio has historically taken a cautious stance on Bitcoin. In his earlier assessments, he warned governments could eventually move against it:

"If it becomes really successful, they will kill it. And they have ways of killing it."  Dalio told CNBC in 2021.

But by late 2021 and into 2022, Dalio softened his tone as Bitcoin gained broader adoption, acknowledging it had proven durability compared to early skepticism: