The world of initial coin offerings (ICOs) is attracting so much interest that some investors are able to double their money—on paper—before an offering has even begun. This is the case with the chat app Telegram, which is targeting a blockbuster $1.2 billion ICO.

The offering is due to open to the general public in March, but investors who got in on an earlier, private investment round, are already flipping their GRAM cryptotokens for twice the price they paid, according to sale documents seen by Quartz.

While investors commonly sell part of an allocation in an upcoming ICO to others, the level of interest in the Telegram offering is at a fever pitch, market watchers say. “Telegram is definitely much more crazy than some of the bigger ICOs we have seen,” says Sid Kalla, a founder of ICO consultancy Smith and Crown, who now works on token protocol-design as a founder at the Turing Group.

One reason buyers are snapping up the Telegram offering could be down to its audacious size. Kalla points out that as the ranks of hedge funds investing in crypto offerings have grown, the opportunity to place big bets has shrunk. “Telegram offers them one shot at putting a lot of money to work at one go,” he says.

Telegram split its token offering into two tranches. It plans to raise $600 million in a so-called private sale to institutional investors that closes at the end of this month. The Financial Times reported (paywall) that the round includes $60 million from some of Silicon Valley’s biggest venture capital firms, including Google backer Kleiner Perkins and Uber investor Benchmark. Another $600 million would then be raised from the general public starting in March, bringing the total raised to $1.2 billion. (That’s a hefty sum for a company that listed only 15 developers in its offer documents.)

Private-round investors should have paid $0.30 a token, according to estimates from Telegram’s offering documents. (It gets complicated because the price of a token changes depending on the size of the offering.) Quartz contacted Telegram but didn’t receive a response.

Some of these early investors are already flipping their allocations in the round for as much as double the offering price. According to an email seen by Quartz, early investors are selling large blocks of their allocations for millions of dollars. One tranche of 5.3 million GRAM tokens was going for $0.60 a token, putting the total price, inclusive of fees for the transaction, at $3.2 million. Another tranche of the same size, from a separate seller, was offered at $0.57 cents a token, carrying a price tag of $3 million.

The email offering the blocks was sent by a broker to a venture capitalist in the US. The broker was seeking accredited investors to buy the blocks from his clients. The sellers were named as a private equity firm in Hong Kong, AID Partners, and an unnamed “prominent” venture capitalist in Singapore. AID Partners didn’t respond to emails and calls to its offices.

The email explained that the sellers were personally invested in the ICO, but wanted to dispose of part of their allocations. The broker was keen to suggest that the deal was hot. “The [sellers] are oversubscribed and will allocate this on a first-come, first-served, basis as most wires have already been coming in,” the broker wrote in the email. ”We need to get the buyer on the phone with the seller today. The seller will only speak to the actual buyer. A deposit must be wired or proof of wire as soon as possible.”

There are generally two ways for early investors to sell their holdings. The first is for both buyer and seller to enter into a contract called a SAFT—a “simple agreement for future tokens“—that has become the de facto way token sales are conducted. Under the terms of a SAFT, the seller promises to hand over the tokens to the buyer at a future date at an agreed upon price. (In other words, a futures contract.)

The second way is for a seller to create a special-purpose vehicle, usually a limited liability company, to which ownership of the tokens, or of rights to the tokens in the form of a SAFT, is transferred. The seller then cashes out by selling equity stakes in the vehicle.

One dynamic that has emerged from the Telegram token sale has been its attractiveness to big-name investors, while old hands in crypto investing have stayed away, as Recode and Bloomberg have reported. Several well-known crypto-investors who spoke with Quartz said they weren’t buying because of concerns over pricing and the project’s soaring ambition. “[It’s] raising too much money for a small team,” said Vinny Lingham, the founder of a blockchain identity startup called Civic and a partner at the investment fund Multicoin Capital. He added that the project’s deadlines appear to be too tight for its scale.

While the advent of the ICO has promised near-instant liquidity to investors, the Telegram fundraising takes this to the extreme. Investors are trading Telegram tokens even before the private sale is over, and before a single line of code has been written for the promised Telegram Open Network (TON) that the ICO is funding. The TON project promises to offer micropayments within the Telegram platform, distributed file sharing, and other services. The TON Wallet will eventually become the world’s “most adopted” cryptocurrency wallet, Telegram claims.

One venture capitalist, Michael Jackson of Mangrove Capital Partners in Luxembourg, who isn’t participating in Telegram’s offering, says of the frenzy: “It’s an interesting case—but only for the brave. As in, very, very, brave. It makes normal crypto look blue-chip.”