Bitcoin is crashing -- upward. It just passed $28,000 and shows no signs of stopping. The digital currency has a market value north of $500 billion. Think Bitcoin is just a fad? It's worth more than Visa (V) or Mastercard (MA). Or Walmart (WMT). Bitcoin passed $20,000 for the first time just 11 days ago. Now it's knocking at $30,000's door. Its rapid rise has been remarkable -- or insane, depending on your appetite for risk. But there's some logic to the run-up: Investors are pouring money into bitcoin and other cryptocurrencies during the Covid-19 pandemic as the Federal Reserve sent interest rates near zero (and expects to keep them there for several more years), severely weakening the US dollar. That makes bitcoin, comparatively, an attractive currency. There's a set limit to the number of bitcoins on the planet, and investors believe that once the supply runs out, the digital coin's value can only increase. Also aiding in bitcoin's soaring valuation: Big, name-brand investors are stockpiling it, and huge consumer companies are embracing it. That's adding a dose of validity and appeal to cryptocurrency for mainstream investors. For example, a top executive at BlackRock (BLK) recently said the cryptocurrency can replace gold, and Square (SQ) and PayPal (PYPL) have both embraced bitcoin.

But with Bitcoin capturing greater attention, it could also garner further scrutiny from regulators, says Guy Hirsch, managing director for the U.S. at online-trading platform eToro. "Despite this meteoric rise, there are some storm clouds on the horizon," he said, including the fallout from several last-minute actions by the outgoing Trump administration, among others. Going forward, many strategists and investors say, the industry could see more scrutiny and tighter regulation with Biden in the White House. A lot will, of course, depend on who fills key positions within the administration. Janet Yellen, who's been nominated to serve as Treasury secretary in Biden's administration, has in recent years cautioned investors over Bitcoin, saying it was a "highly speculative asset" and "not a stable store of value." A representative didn't immediately return a request seeking comment.

Meanwhile, Bloomberg News reported that Gary Gensler could be nominated to replace Jay Clayton at the U.S. Securities and Exchange Commission. Clayton's exit from the regulator is welcome news for crypto fans who saw him take a hard line over the years, suing to halt initial coin offerings, rejecting applications for Bitcoin exchange-traded funds and launching a last-minute lawsuit against Ripple Labs Inc. Gensler, who served as a Commodity Futures Trading Commission chairman during the Obama administration, is a senior advisor to the MIT Media Lab Digital Currency Initiative and teaches about blockchain technology and digital currencies. According to eToro's Hirsch, there is uncertainty around how the Biden administration will approach cryptocurrencies, but the appointments are notable "because Yellen is famously anti-crypto and Gensler is known for being pro-crypto."