As the hype around the approval of the first spot Bitcoin (BTC-USD) exchange-traded funds (ETFs) is well and truly over, the sentiment in the cryptocurrency market has cooled appreciably. The Bitcoin fear index now sits at a lukewarm 63, down from 76 just a week ago, which would have been interpreted as an “extreme greed” rating. It seems that some were left disappointed by the market’s reaction to the U.S. Securities and Exchange Commission’s (SEC) approval, and some have taken cover as the currency tests its $42,000 support level.

The good news is that, over the long-term, many analysts believe that the SEC’s decision will be accretive for Bitcoin’s price. But some more defensive positions may need to be taken by those who are more cautious. That can be accomplished by investing in some of these best Bitcoin ETFs.

Some of the ETFs discussed in this article may be seen as a diversified hedge since they have assets under management (AUM) that consist of bitcoin mining companies, energy companies and bitcoin futures. Furthermore, these best Bitcoin ETFs are less volatile, making them inherently less risky than spot Bitcoin ETFs or those that track Bitcoin’s price entirely via derivatives. This could calm nervous investors.

Siren Nasdaq NexGen Economy ETF (BLCN)

The Siren Nasdaq NexGen Economy ETF (NASDAQ:BLCN) is one of the best Bitcoin ETFs for nervous investors. BLCN gives investors indirect exposure to the cryptocurrency market by focusing its investments in companies involved in blockchain technology. Its AUM represent a broad spectrum of industries that range from technology to communications, and its concentration of these assets is equally diverse, with only 35% in its top 10 holdings.

BLCN offers fair pricing and maintains a reasonable expense ratio. Its net asset value (NAV) is $22.55, which is closely comparable to its share price of $22.31. It has net assets of $68,222,759 and an expense ratio of 0.68%.

Some of its largest holdings include names like MicroStrategy (NASDAQ:MSTR) and Marathon Digital Holdings (NASDAQ:MARA), with MSTR stock representing 9.37% of its total weighting in AUM.

For investors who prefer to invest in the picks and shovels of the blockchain industry and shelter from some of the market’s volatility, BLCN could be a valid choice.

Global X Blockchain & Bitcoin Strategy ETF (BITS)

If an investor is after a blended mix of investing in Bitcoin futures and shares of blockchain development and infrastructure companies, then Global X Blockchain & Bitcoin Strategy ETF (NASDAQ:BITS) could be the ticket.

While it’s true that blockchain stocks may follow a close correlation with Bitcoin and the broader crypto market, the strength of this correlation waxes and wanes, and there’s a stronger correlation between indices like the Nasdaq than the crypto market.

BITS has a 44.22% exposure for its AUM to another ETF named Global X Blockchain ETF (NASDAQ:BKCH), with the remainder in short-term futures dated for the current and next month. BKCH then invests in popular crypto brands such as Coinbase (NASDAQ:COIN) and some of BLCN’s holdings. BITS is also fairly priced to its NAV, and has an expense ratio of 0.65%.

CI Galaxy Bitcoin ETF (PNK)

The CI Galaxy Bitcoin ETF (CGBCF:PNK) is a valid option for investors since, unlike other ETFs, it holds all of its Bitcoin in segregated cold storage. This may give some assurance that it actually holds the funds it promises to keep under management, which is a serious point of contention among investors with the newly-approved spot Bitcoin ETFs.

Cold storage means that it’s significantly more difficult for customer’s funds to go missing amid a hack or cyber attack since the wallets that hold the Bitcoin are not connected to the internet. For those who have seen the disasters of institutional wallets being hacked in the past and want to avoid the possibility of it happening to their own investments, PNK could be a viable option to consider.

A management fee of 0.4% is also competitive with many of the leading blockchain ETFs on the market.

On the date of publication, Matthew Farley did not hold (either directly or indirectly) any positions in the securities mentioned in this article. The opinions expressed are those of the writer, subject to the InvestorPlace.com Publishing Guidelines.