Investing in cryptocurrencies is complicated. Four new trusts make it easier, says crypto investor Michael Sonnenshein.

"Digital currencies are not like stocks and bonds and all the other things that you buy," Sonnenshein, managing director at Grayscale Investments, a digital currency investment firm, said Monday on CNBC's "Fast Money." "There's certain technological prowess that people need to have in order to handle them, store them securely, et cetera."

Recognizing that investors want exposure to digital currencies, Grayscale launched four new crypto funds: Bitcoin Cash Investment Trust, Ethereum Investment Trust, Litecoin Investment Trust and XRP Investment Trust.

Grayscale is the creator of the popular Bitcoin Investment Trust (GBTC), a way to invest in and trade the price moves of bitcoin without directly investing in the digital currency.

The new trusts, Sonnenshein said, are "something that people can really wrap their heads around."

So far, in the week since the products were introduced, the demand has been "fantastic," said Sonnenshein, whose company has approximately $2.1 billion in assets under management across eight different products.

"There's a lot of investors who want to be able to place targeted exposure in a fund," he said.

"And, there are also investors who want that more-diversified exposure, like the digital large-cap fund offers."

"We're continuing to break records all the time," Sonnenshein said.

He said each fund operates as a trust on a rules-based methodology, where tokens are evaluated each quarter to see if they have fallen into the 70 percent target of the overall market cap in digital currencies.

"Of course there are other qualifiers and disqualifiers: There's got to be a liquid market. We have to have a custodial solution that we feel really is secure and robust and allows us to continue to operationally support the product," Sonnenshein said.

Each fund has a one-year holding period before it can be resold without restrictions. Only U.S. qualified accredited investors can put money into funds. Sonnenshein said Grayscale plans to roll out more new products later this year.