Venture capitalist and Union Square Ventures co-founder Fred Wilson believes there's a cryptocurrency crash coming – and he thinks investors need to diversify in order to prepare.

In a new blog post, Wilson recounted his experiences during the dot-com boom and bust of the late 1990s and early 2000s, during which a number of then-well-known internet firms rose to prominence and subsequently failed, taking many investors with them.

Wilson said that he lost as much as 90% of his net worth at the time, saved only by a pair of real estate holdings. It's that experience, he wrote, that has informed his investment decisions ever since – including the choice to keep a diversified portfolio that includes other assets along with cryptocurrencies.

Relating a conversation with a friend, he said the two discussed "inevitability of a massive crash" in the cryptocurrency space, writing:

Experiences in the dot-com crash aside, Wilson stated that he still believes people should invest in the market.

"I have advocated many times on this blog that people should have some percentage of their net worth in crypto," he wrote. "I have suggested as much as 10% or even 20% for people who are young or who are true believers. I continue to believe that and advocate for that."

That said, Wilson isn't saying that people should go all-in on the market. Quite the contrary: in his post, Wilson called for the kind of smart investment planning that he he learned about "the hard way" when the tech bubble collapsed.

"I wish I had done it during the internet boom. I did not, but the next time we made a bunch of money, I did. I learned the hard way. I share my story so that others don’t have to," he wrote.

Image via CoinDesk