Wrapped Bitcoin: BiT Global's Nadia Song on Custody, Competition and What Bitcoin Does in DeFi

In the latest episode of the Bullish on Bitcoin Show, BOB co-founder Alexei Zamyatin hosted Nadia Song of BiT Global, the company behind Wrapped BTC (WBTC) — the asset that, more than any other, is the reason Bitcoin has a seat in DeFi at all.

Here's a rundown of the highlights.

How WBTC happened

The premise in 2019 was simple to state and hard to execute. They loved Bitcoin, they thought Bitcoin should do more, and Ethereum was where everything was happening. If Bitcoin could be collateral, or liquidity or a tradable asset over there, the whole ecosystem would be better off.

The obstacle was Bitcoin itself. As Nadia put it, on its native chain it can't do much - and there's no fixing that from the outside. You can't find Satoshi. He's gone. You can't upgrade the contract. So they wrapped it and sent it to Ethereum.

It started at a few hundred coins and stayed small. Then DeFi summer arrived, Maker DAO listed WBTC as collateral, and the line went vertical into the tens of thousands of WBTC. Her explanation for why Bitcoin specifically, rather than any other asset: almost everyone's first crypto purchase is BTC or ETH, so when people realised Bitcoin had a use beyond sitting still, they already held it.

The custody argument - and a host conceding it

WBTC's permanent objection is that it's custodial, and Nadia doesn't fight the premise. Her answer is transparency: one-to-one proof of reserves published on the site, so nobody has to take the brand's word for it.

“I'm not asking you to trust WBTC because of its reputation. Users should be able to independently verify that every WBTC is backed.”

She's also explicit about what WBTC isn't for. Self-custody is Bitcoin's core principle, she respects it, and WBTC was never meant to replace holding your own coins. It's for people who want their Bitcoin doing something. Different users have different trust models; institutions want regulated custody, operational controls and auditable processes, and they want someone accountable. On the roughly 116,000 BTC behind the asset, she asked the room:

“Are you sure you really don't want someone to answer for it?”

The unusual part was Alexei taking her side against his own earlier work. He did a PhD on crosschain bridge security, co-authored the BitVM 2 papers, and spent years building trust-minimized designs meant to make WBTC unnecessary. On air, he conceded it: the market wanted institutional custody with visible reserves.

There is always custody involved when Bitcoin is bridged, because Bitcoin can't verify other chains - every design just picks a different trade-off. Centralized exchanges sit at one end with no proof of reserves at all, BitVM at the other with cryptographic guarantees and real technical risk. WBTC landed in the middle, and the middle is where the money went.

Running something DeFi can't afford to break

With billions in TVL, WBTC now operates less like a crypto product and more like a systemically important financial utility. Aave, Morpho, Spark, Sky and a long tail of protocols built on top of them all depend on it behaving exactly as it did yesterday.

The cost is speed. Security and legal clarity win every internal argument, and Nadia was candid that this has meant passing on things the team wanted to build. Alexei's observation was that it leaves WBTC oddly similar to Bitcoin itself - constrained by how many people would feel any change. What hasn't changed, she said, is the day-one goal: Bitcoin transcending its native chain, and WBTC as the universal BTC standard across all of them.

Neutral by construction

Asked how she thinks about competitors, Nadia welcomed them - a WBTC that stood still for ten years would be a worse WBTC. But she named the structural reason it keeps winning integrations, and it isn't technology:

“We don't own a chain. We don't own a CEX. We don't have a protocol that we're trying to push liquidity towards.”

Nobody sees WBTC as a competitor, so it ends up integrated across hundreds of protocols. Neutrality is the product. Deep liquidity, published reserves, distributed multi-sig custody and licensing are the rest of it.

She also had a complaint about how the industry competes. The market is shrinking, in her view, and she'd rather everyone worked on where new users come from than on taking each other's. Her example: chains keep coming to her asking how to pull Ethereum users over.

“I was like, no. Can you think of how you can get new traffic?”

The wrapper wars and the minting gap

Coinbase's cbBTC is the one with real traction, with Kraken's kBTC, a Circle announcement and Binance's own arrangements behind it. On Solana, cbBTC is ahead of WBTC by 0.8% of market share, and Nadya was unguarded about why:

“I really envy cbBTC because it's so easy to mint. They have a CEX, you just go there, and then you put your USD, your stables in, and then you get your cbBTC.”

Her read on the split is that the two serve different audiences. Retail takes the one-click path. Institutions move larger amounts, prefer a regulated custodian with deeper liquidity, and don't mind a slower mint and burn. Some of them also look at cbBTC and see a single exchange as a single point of failure - which is its own trust preference, not an absence of one. She expects WBTC to keep dominating Ethereum.

She also flagged the market everyone skips. Asia holds a lot of Bitcoin and almost none of it has been put to work; WBTC has a team there specifically on that.

Alexei's counterpoint was that the minting advantage is narrowing. Through BOB Gateway you can send native Bitcoin and receive WBTC in a single transaction, no exchange account required - and because WBTC's liquidity is so deep, solvers quote it competitively. Nadya asked for more of it, then pointed past it: new users still arrive through centralized exchanges, because Google and AI will cheerfully tell a beginner that DeFi has no custody and no customer service.

What's changed is that exchanges now wire their own wallets into DeFi to stop losing those users - and, both agreed, ended up bringing more people in. Users one step into DeFi are the most convertible audience in crypto.

What people actually do with WBTC

Overwhelmingly, one thing: collateral. Every new lending protocol wants Bitcoin collateral, and WBTC is the default. Trading desks trade it actively.

The use case that has retreated is liquidity provision. Bitcoin's volatility has made LPing punishing enough that Nadya stopped doing it herself. Set-and-forget AMMs are fine for small amounts, she said, but fees are correspondingly small — and at size, without active management, you're playing market maker without meaning to.

Regulation, freezes and quantum

On where regulatory pressure lands first, Nadya doesn't think it's WBTC. She expects decentralized exchanges to feel it first - some already have - and Bitcoin itself to come into view after that. Her compliance team monitors closely and adapts. She counts WBTC as part of DeFi; centralized exchanges, she noted pointedly, are not.

On exploits, she was careful about her answer and honest about why. Once WBTC is in circulation the issuer can't stop anything, and every option is a loss:

“The moment you freeze something, they say, oh, you see, they are so centralized. And then if you don't, they will say, oh, look at them, they don't try and help.”

So: prevention over cure, no comment on the playbook. WBTC security team is already looking at quantum - not because it's urgent, but because an issuer this size has to start early.

Will trust-minimized bridges replace it?

The closing question, from someone with a stake in the answer. Nadya's framing was commercial: whoever gets the institutions gets the market share, because that's where the money is, and institutions doing business with each other still have requirements - security, custody, regulation. Ask them to put Bitcoin somewhere with nobody to hold accountable and they get nervous.

Her team researches these designs and doesn't see a threat - “more of a product for a different market segment.” Retail and crypto-natives will try the new thing; funds will stay with regulated custodians.

Alexei's thesis is that the two converge. Institutions went from simple multisig to MPC, and MPC spent years as academic theory - good for hypothetical poker games - before crypto turned it into infrastructure. He expects BitVM to follow that path: not a replacement for institutional custody but a better way to do it, with less key management risk. Maybe one day WBTC runs on BitVM. Nadya didn't rule it out - “you never know, right?”

Watch the full episode

This recap covers the main threads, but the full conversation goes deeper on the early education work, the CEX-to-DeFi funnel, and the mechanics of bootstrapping liquidity for a new Bitcoin asset. Watch the complete episode of the Bullish on Bitcoin Show with Nadya Song here:

Watch on YouTube →