Last week, Janet Yellen expressed regulatory concerns about crypto. In her confirmation hearing Tuesday, President Joe Biden's Treasury Secretary nominee spelled a hard line stance: "Cryptocurrencies are a particular concern. I think many are used-at least in a transactions sense-mainly for illicit financing." She added she wants the Treasury to "examine ways in which we can curtail their use" and ensure money laundering is not committed via crypto. But 2 days later, Yellen issued another statement qualifying her concern. She conceded the US should "consider the benefits of cryptocurrencies and other digital assets, and the potential they have to improve the efficiency of the financial system," suggesting a more nuanced view of the sector and technology that will crack down on crime but also create rules to encourage fintech innovation.

Here is the rest of the week in review:

BlackRock (BLK  ) approved 2 of its funds for the ability to invest in Bitcoin (BTC) futures. Prospectus documents filed Wednesday with the US Securities and Exchange Commission show that BlackRock Global Allocation Fund and BlackRock Funds V are eyeing Bitcoin by naming it on their lists of derivative products. The filing said: "Certain Funds may engage in futures contracts based on Bitcoin," BlackRock did not disclose which commodity exchanges it will choose to execute any crypto futures trades. The funds can only invest in cash-settled Bitcoin futures, which only the CME (CME  ) offers currently. BlackRock's filings warn that investments in these futures could carry illiquidity risks due to the "relatively new" market, as well as adverse impacts from regulatory changes, valuation, and volatility.

Valkyrie Digital Assets on Friday filed an application for a new Bitcoin exchange-traded fund (ETF). If approved by the SEC, the Valkyrie Bitcoin Fund would be listed on the New York Stock Exchange, with Coinbase Custody Trust Company serving as the custodian, according to Dallas-based Valkyrie Investments. Valkyrie CEO Leah Wald said: "Our executive team has previously launched multiple ETFs, publicly traded funds, and ETPs, including Bitcoin funds." Valkyrie's application is the second in recent times, after VanEck resubmitted its application to the SEC in hopes of approval from the Biden administration. The SEC previously rejected all 9 ETF proposals in August 2018 by citing market volatility and industry manipulation, temporarily closing the door to Wall Street's dream. But many in the crypto space believe incoming SEC chair Gary Gensler will be friendlier to crypto and could be persuaded to approve ETFs.

Crypto prices slipped to $929 billion this week, largely due to Yellen's critical comments and a Bitcoin double spend report by BitMEX that was later debunked by blockchain experts. For the majors, Bitcoin, Bitcoin Cash (BCH), and Cardano (ADA) posted outsized losses, while Chainlink (LINK) and Ether (ETH) bucked the market trend with gains. In the top 100, the biggest losers were Dash (DASH), down 16%, Augur (REP), down 14%, and Monero (XMR), down 14%. The biggest gainers were Enjin Coin (ENJ), up a whopping 62%, Decentraland (MANA), up 53%, and Hedera Hashgraph (HBAR), up 48%. Next week traders will watch if Bitcoin can bounce back.

The author owns a small amount of BTC.