The first half of 2021 brought a crypto boom and bust as bitcoin hit a new all-time high in April and then completely erased all its annual gains (and then some) by July.

Now, as bitcoin (BTC-USD) finds its footing, bulls are reloading for what they say will bring an exciting conclusion in the back half of the year.

Whether or not the world of crypto delivers on the high hopes investors have for what's left of 2021, Yahoo Finance can at least guarantee that the action is likely to involve the names we've singled out as the top leaders to watch below (in no particular order):

Barry Silbert

Beginning with a big bet on bitcoin being a game changer back in 2012, Barry Silbert's impeccable run as the founder of crypto venture fund Digital Currency Group has continued ever since. Not only has he built Grayscale Investments into the largest digital asset manager in the world as it helped institutions tap the crypto market through its trusts, but other wins have stacked up as well. Through DCG, which he founded in 2015, Silbert has invested in nearly all the corners of crypto today — from news (CoinDesk), to data (CoinMetrics), to exchanges (Coinbase) and payments and stablecoins (Circle.)

Sam Bankman-Fried

As a 29-year-old multibillionaire who founded one of the fastest-growing crypto exchanges in FTX, Sam Bankman-Fried certainly boasts the resumé to appear atop any list of crypto leaders. FTX's latest round of financing set a crypto record by bringing in $900 million from the likes of famed VC firm Sequoia Capital and even Coinbase's venture arm, among others. It also cemented an incredible rise in its valuation — from $1.2 billion last year to $18 billion now. Looking ahead with all that cash, the company could easily make a splash with acquisitions — something Bankman-Fried emphasized as a priority in his latest interview with Yahoo Finance.

Aside from the branding partnerships FTX has put together to draw sports fans into crypto through their deals with Major League Baseball (for brand patches on MLB umpire uniforms) or the National Basketball League (for naming rights to the arena the Miami Heat call home), the company now also counts Super Bowl Champion Tom Brady among its list of investors. As a constant surrounding of fans at the Bitcoin 2021 Conference in Miami proved, Bankman-Fried has a loyal following in crypto and the respect of the sector.

Jack Dorsey

From appearing as a headline speaker at the Bitcoin 2021 Conference to goading Elon Musk into a sit down at the B Word virtual conference, Square and Twitter CEO Jack Dorsey has been stepping up his bitcoin game in a big way this year. Through Square, Dorsey is launching a new effort, dubbed TBD, to build out decentralized finance capabilities on bitcoin. The company also purchased more than $200 million in bitcoin to add to its balance sheet so far this year as it continues to lean into crypto.

Elon Musk

Perhaps no one has proven more sway on crypto markets in 2021 than Tesla CEO Elon Musk. Many attribute his tweets about the cryptocurrency as a major catalyst to hit the new all-time high, if they weren't already boosted enough by Tesla's $1.5 billion bitcoin purchase. Just as quickly, Musk may have triggered a complete price reversal with Tesla's about face on accepting bitcoin for payment in May. Bitcoin proceeded to tank 50% in the aftermath, and Musk's sentiment on social media quickly turned. Similarly, many attribute his Saturday Night Live appearance as a catalyst for the downward moves in Dogecoin (DOGE-USD) after Musk called it "a hustle."

But as he expressed alongside Jack Dorsey at the virtual B Word conference, he remains a net fan of crypto and most likely sees Tesla returning to accepting bitcoin once again.

The Sharks: Mark Cuban and Kevin O'Leary

If ever there was a sign of bitcoin fully crossing over into the traditional investment world, it may have been Shark Tank's Kevin O'Leary revealing to Yahoo Finance that he had dedicated 3% of his portfolio to it. While that allocation isn't going to turn heads relative to anyone else on the list, O'Leary proved he had an understanding of how institutional investors might be looking at the space. His warning over sustainability issues around bitcoin mining pre-dated Elon Musk's about face and proved salient. A week later, bitcoin began its 50% collapse. Now, he thinks bitcoin is poised to outperform stocks.

For his part, fellow shark Mark Cuban has seemed more interested in the promises offered by decentralized finance. While Cuban fell victim to the collapse of DeFi project Iron Finance, he's been calling attention to the opportunities in the space (and the regulations that might be needed to protect consumers.)

The BlockFi co-founders: Zac Prince and Flori Marquez

As crypto grew, Zac Prince and Flori Marquez set out in 2017 to build a lending platform that investors could turn to outside of traditional finance. Now, their platform, BlockFi, is a leader in the space with a $3 billion valuation, boasting capital from the likes of Fidelity, Coinbase Ventures and SoFi. Importantly, the platform has also offered a way for savers to earn yield at a time when interest rates are at historic lows. BlockFi pays more than 7% interest on stablecoins, which unlike bitcoin and other cryptos, are designed to not waver from their $1 peg.

However, as the company crossed more than 265,000 retail clients in March, it also drew the attention of regulators. In July, New Jersey and a smattering of other states, including Texas and Vermont, took issue with the interest bearing accounts that BlockFi offered. Other regulators might soon step up the pressure on lending platforms like BlockFi, which is very careful to not call itself a bank. How they respond to that pressure could explain why less centralized lending platforms were needed all along (or not.)

Caitlin Long, Avanti Financial Group CEO

Standing apart from the lending platforms in crypto that are careful not to call themselves banks, sits Avanti Financial and its founder Caitlin Long. Long, a 22-year veteran of Wall Street, set out to create Avanti as a much needed stopgap between the world of digital assets the legacy financial system. She also spent two years helping Wyoming officials research and write the laws that put the state on the map as a blueprint for regulating bitcoin.

Avanti won its banking charter in October 2020. Now, Long is championing how to build out crypto banks the right way and advising the sector on ways to avoid the same pitfalls that brought down the traditional banking system in 2008. She has spoken out against leverage and has closely monitored the Fed for inklings of changes when it comes to regulating crypto.

Jesse Powell, Kraken CEO

Coinbase may have been the first major crypto exchange to list in the U.S., but Kraken likely isn't that far behind. Jesse Powell, who heads the exchange with more than 6 million clients, said the company could look to go public in little over a year's time. The company was recently in talks to raise new funding that would value it at more than $10 billion, according to Bloomberg.

Kraken also won the first banking charter for a digital assets company in September 2020, kicking off plans to also be a trusted connector between traditional finance and crypto.

Chris Dixon and Kathryn Haun, Andreessen Horowitz's Crypto Fund III

Led by Chris Dixon and Kathryn Haun, Andreessen Horowitz's Crypto Fund III set a record as the largest crypto-focused VC fund yet announced at $2.2 billion. Dixon and Huan, a former federal prosecutor and a16z's first female general partner, will look to build on the VC firm's 2013, $25 million bet on Coinbase.

"The size of this fund speaks to the size of the opportunity before us: crypto is not only the future of finance but, as with the internet in the early days, is poised to transform all aspects of our lives," said the duo of Coinbase board members in a blog post announcing the fund back in June.

Vitalik Buterin, Ethereum co-founder

As the most prominent (known) founder in the world of crypto, 27-year-old Ethereum founder Vitalik Buterin is perhaps the most obvious name on any crypto list. Ethereum (ETH-USD) has swelled to outperform bitcoin over the last year by a factor of two, up 592% over that time frame. The chain has largely benefitted from coders using Ethereum to build other projects, including NFTs (non-fungible tokens) and decentralized finance applications.

Buterin, who normally keeps a relatively low profile by crypto's standards, has been branching out lately, even going as far as voice acting in a new animated series with Ashton Kutcher and Mila Kunis to spotlight NFT cats.

Mike Novogratz, Galaxy Digital founder

Ever the standout, former hedge fund manager Mike Novogratz has racked up a number of crypto wins since diving into the space. His crypto assets company Galaxy Digital also made waves this year with the largest-ever deal in the sector by buying crypto custody firm BitGo in a $1.2 billion deal. The combined entity will boast more than $40 billion in assets under custody and emerge as a complete one-stop crypto shop when the deal closes.

The company, which added a mining business unit in March, is looking to list on a U.S. exchange later this year. Galaxy currently trades on Canada's Toronto Stock Exchange.

When asked at Bitcoin 2021 Conference in Miami if it might be fair to compare his investing intuition in crypto to Warren Buffett's track record in stocks, the billionaire Novogratz joked, "Well, I am the oldest guy in crypto."

Erik Voorhees, ShapeShift CEO

After selling his bitcoin gambling site Satoshi Dice in 2013 for more than 125,000 bitcoins, Erik Vorhees founded original crypto swapping platform ShapeShift in 2014. The company eventually lost nearly all of its customers when it was forced to comply with know-your-customer (KYC) rules as an exchange. But since then, ShapeShift has rebuilt itself using decentralized applications on the backend to power crypto swaps without having to follow the same rules in asking customers for identifying information.

Voorhees took things a step further in July when he fully embraced decentralization and announced his company would be tokenizing itself as a decentralized entity owned by its customers and community members. Voorhees predicted other crypto companies would follow in the ShapeShift decentralization model.

Gary Gensler, chairman of the Securities and Exchange Commission

While you likely won't find SEC Chair Gary Gensler on the top of any crypto influencer list it's hard to think of someone more influential — and for a change as a crypto regulator — more knowledgeable. Gensler previously taught a course on blockchain technology and crypto at the Massachusetts Institute of Technology, during which he described himself as a "center minimalist" on bitcoin. While the SEC has been pretty muted on new crypto regulations in his short tenure so far, approving one of the more than a dozen of bitcoin ETF applications could quickly change that.

As Galaxy Digital CEO Mike Novogratz said about him: "Gary Gensler is a smart guy. I trust that he's going to come out with smart regulations." As he said about Gensler approving a bitcoin ETF, it could unlock a massive wave of wealth held by older Americans.

"The big wealth in America is 50- to 80-year-olds, they typically work through RIAs, registered investment advisors. They're slower to buy in — that trend has started — the ETF just makes it easier,” he said.

Anthony Pompliano, Pomp Investments founder

As the co-founder of crypto hedge fund Morgan Creek Digital, Anthony Pompliano could have a spot on this list though his investment focus alone. Not only does Pompliano boast early investments in BlockFi and eToro, the man they call "Pomp" has built up an impressive following on social media by focusing squarely on bitcoin. He recently crossed more than 1 million followers on Twitter, and continues to build out his crypto-focused podcast highlighting crypto startups and innovators.

Brian Armstrong, Coinbase CEO

As co-founder and CEO of Coinbase, Brian Armstrong brought the company across the direct listing finish line in April to make the crypto exchange the largest public company of its kind. As one of the larger exchanges, Coinbase has important power in adding some of the more fringe crypto projects to its platform. Earlier this year, Dogecoin saw a bit of a pop after the company announced it would be adding the cryptocurrency to the platform. Armstrong has also signed on to the Giving Pledge, joining Warren Buffett in signaling his goal to give away a substantial amount of his fortune.

Paul Tudor Jones

Legendary investor Paul Tudor Jones created a wave that rippled through the hedge fund world when he seemingly endorsed bitcoin as a hedge against inflation in a May 2020 investor letter. He doubled down on that stance last December right before bitcoin began its tear higher. Many on the institutional side of the trade credit his letter as a spark to other investors and hedge funds jumping on the crypto wagon.

Pantera Capital’s Dan Morehead

Pantera Capital is an absolute crypto juggernaut. Founded by Dan Morehead, it bills itself as the first U.S. institutional asset manager focused exclusively on cryptocurrency and blockchain technology. It has already racked up big wins through investments in exchange Bitstamp, USDC stablecoin issuer Circle, and custody firm BitGo and a bevy of others.

Morehead, who got his start at Goldman Sachs, predicted bitcoin could hit $115,000 by August in an interview with Yahoo Finance earlier this year. His investor letters offer an incredible data-driven look at the broader crypto space.

Alex Mashinsky, Celsius CEO

As the head of one of the world's largest crypto lending platforms, it's impressive that Alex Mashinsky still finds time to host frequent YouTube video updates for customers. Similar to BlockFi, Celsius has grown to attract more than 107,000 bitcoins from customers by offering a way to earn interest and take out loans using crypto as collateral. Unlike BlockFi, Celsius uses a company token to facilitate some of the utility of its platform. As the crypto lending sector continues to grow, it's clear Celsius will also continue to attract the attention of regulators. Earlier this year, concerns about its lending practices were raised when a report claimed the company's custodian pulled out over excessive re-hypothecation, a claim Mashinsky vehemently denied to Yahoo Finance.

Mashinsky has also been quite outspoken against the role Elon Musk has played in the world of crypto. At the Bitcoin 2021 Conference in Miami, Mashinsky made headlines by calling Musk a "tourist" in crypto who was only looking to gain followers.

Zack Guzman is an anchor for Yahoo Finance Live as well as a senior writer covering entrepreneurship, crypto, cannabis, startups, and breaking news at Yahoo Finance. Follow him on Twitter @zGuz.

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