The former Chair of the U.S. Securities and Exchange Commission (SEC) Gary Gensler is warning that the future of non-Bitcoin (BTC) crypto assets is looking bleak.

In a new interview on CNBC’s Squawk Box, Gensler says that most altcoins lack solid economic fundamentals and are almost entirely propped up by sentiment, putting them at high risk of a sudden collapse.

“If you were interested in [crypto], think about [how] every financial asset sort of trades on a bit of fundamentals and sentiment, but this field is almost 99% – or maybe one might say 100% – sentiment and very little on fundamentals. And while something like Bitcoin may persist for a long time, because there’s 7 billion people around the globe, a real keen interest in it, there’s 10,000 or 15,000 others of these tokens, and to think through your own risk, your own personal risk, about where are the fundamentals, and if this is just about sentiment, then generally those don’t end up well, and most then go down…

Think of these 10,000 or 15,000 other tokens, and just on the economics, just on the fundamentals, what are the fundamentals?”

When asked if Bitcoin (BTC) is a different case than the tokens he is warning about, Gensler compares the flagship crypto asset to gold, noting that out of the eight precious metals in existence, most people only care about gold and silver.

“I think the distinction is similar to in metals, there’s only two or three precious metals. We humans have a certain fascination with two or three precious metals like gold. I don’t think we humans will have a fascination with 10,000 or 15,000 meme or sentiment tokens trading over the years.”