The cryptocurrency craze is finally flowing into the exchange-traded funds business.

Investors poured about $240 million into two blockchain-focused ETFs since their launch last week, according to the latest available data from FactSet. Blockchain is the technology behind bitcoin and other cryptocurrencies.

The surge of interest came even as bitcoin, the largest digital currency by market capitalization, stagnated in price in the last week. Bitcoin has fallen nearly 7 percent in the last week to about $10,800 Friday on Coinbase, the leading U.S. exchange for major cryptocurrencies.

Bitcoin performance in the last week

Source: Coinbase

"It is rare for new ETFs to pull in such a large amount of cash," Todd Rosenbluth, CFRA's director of ETF and mutual fund research, wrote in an email, "but there has been pent-up demand for a thematic approach to gain exposure to Blockchain."

Amplify Transformation Data Sharing ETF (BLOK), whose top holdings include Taiwan Semiconductor Manufacturing and Overstock.com, saw assets under management leap to $164.9 million Wednesday from just $2 million a week ago, according to FactSet. Chipmakers such as Taiwan Semiconductor have reported a sales surge due to demand from cryptocurrency "miners." E-commerce company Overstock.com has a division focused on developing and investing in blockchain-related businesses.

The Reality Shares Nasdaq NexGen Economy ETF (BLCN) holds stocks such as IBM, which is developing a number of enterprise blockchain projects, and SBI Holdings, which is a prominent Japanese financial services company working with cryptocurrencies. The BLCN ETF's assets under management multiplied just over nine times in a week to $86.27 million, FactSet data showed.