Ark Investment Management founder and CEO Catherine Wood is a big believer in bitcoin, which has seen a rise of more than 1,300 percent so far this year.

Bitcoin is "so much bigger an idea than even Apple, which is a pretty big idea," Wood said Thursday on CNBC's "Halftime Report."

Wood said her fund can't own the cryptocurrency directly, so it bought shares of Bitcoin Investment Trust (GBTC) in 2015 when bitcoin traded below $250 to get exposure.

GBTC bills itself as the first publicly traded security "solely invested in and deriving value from the price of bitcoin," according to trust creator Grayscale.

The trust was down about 8 percent to $1,981 per share Thursday, while the price of bitcoin declined about 10 percent to around $13,878, according to CoinDesk.

GBTC holds about 0.092 bitcoin per share. So at about one-tenth the price of bitcoin, the trust was trading at more than a 40 percent premium Thursday.

Wood also said bitcoin may split in the future, so it can be a true digital payment solution without any transaction limit issues.

"Maybe [bitcoin] will do a hard fork, so it has both the store of value role and the means of exchange role," she added.

She downplayed the "bitcoin cash" fork because it's subject to the same maximum 21 million coin limit rule as bitcoin.

Ark is an investment management firm focused on disruptive technology.

Before starting Ark, Wood spent 12 years at AllianceBernstein as chief investment officer of global thematic strategies, where she managed $5 billion.