BKC traded little changed Wednesday morning near $25.14 a share. As of launch, the ETF's five largest holdings were: Taiwan Semiconductor Manufacturing , Global Unichip, GMO Internet , Overstock.com and SVB Financial Group . Each had an 8 percent weighting in the ETF.

The REX BKCM ETF (BKC) holds shares of 32 companies working in cryptocurrencies or their underlying blockchain technology. The ETF is run by Rex Shares and actively managed by Brian Kelly, a CNBC contributor and head of BKCM, which runs a digital assets strategy for clients.

The fund also holds shares of Square and chipmaker Advanced Micro Devices. It has an expense ratio of 0.88 percent.

"I get asked all the time on how to invest in blockchain technology without dealing with storage, the fears of hacking, hedge funds, etc. My hope is the BKC ETF can provide this desired equity allocation to institutions and individuals alike," Kelly said in a statement.

Bitcoin is the first application of blockchain technology, which quickly creates a permanent record of transactions between two parties and eliminates the need for a third party, such as a bank. Prices of bitcoin and other cryptocurrencies have skyrocketed in the last 18 months on increased investor interest. However, the Securities and Exchange Commission has not yet allowed a bitcoin ETF to list due to issues such as liquidity and extreme price volatility.

Four other blockchain ETFs launched in the U.S. in January: First Trust Indxx Innovative Transaction & Process ETF (LEGR), Reality Shares Nasdaq NexGen Economy ETF (BLCN), Amplify Transformational Data Sharing ETF (BLOK) and Innovation Shares NextGen Protocol ETF (KOIN).

All four funds fell single digits from the end of January to the end of March, but are up slightly for the second quarter so far.