North America’s largest cryptocurrency exchange, Coinbase, has opened its new index fund to large investments. According to a Medium post published yesterday, the fund is now open for investments ranging from $250,000 to $20 million. The fund, which uses market capitalized weightings, tracks the Coinbase Index. At this moment, the index lists four cryptos—bitcoin, bitcoin cash, ethereum and litecoin—and has plans to list ethereum classic in the “next few months.” (See also: Coinbase Launches Cryptocurrency Index Fund.

The San Francisco-based company has seen “overwhelming interest” from accredited investors since it announced the fund in March this year, according to Reuben Bramanathan, product lead at Coinbase Asset Management. The fund’s performance has mirrored the slump in crypto markets, with a three-month return of -7.20% for three months as of May 1.

To be sure, Coinbase is not the only startup vying for a slice of the growing index fund market for cryptocurrencies. Bitwise Asset Management started a crypto index fund in December that tracks the top 10 cryptocurrencies. (See also: Crypto Index Fund Delivered 45% Returns In First Two Months.) 

The Holy Grail: A Crypto ETF

New York-based Grayscale Investments is the pioneer. It launched the Bitcoin Investment Trust, which trades in OTC markets, in September 2013. As of the end of April, the fund has returns of 6,577.14% since inception. But it lost 10.98% of its value in the preceding three months. As this Fortune article points out, Coinbase has a leg up on other funds because it charges lower management fees. 

But the holy grail—an ETF targeted at retail investors—still remains elusive. In a February letter, the SEC outlined its reasons for not allowing an ETF. These ranged from the lack of regulation at crypto exchanges (which are used to derive crypto prices) to the absence of custody solutions. (See also: Why Is the SEC Afraid of Bitcoin ETFs?)

Coinbase is methodically plugging those gaps. It announced a custody solution targeted at institutional investors earlier this year and has filed with the SEC to become a broker for cryptocurrencies. The company is often referred to as the “Goldman Sachs” of bitcoin and has ambitions to become the “Google of crypto."