Former Mt. Gox CEO proposes hard fork to recover $5.2 billion in bitcoin from 2011 theft

Mark Karpelès, the former CEO of defunct crypto exchange Mt. Gox, has published a proposal calling for a Bitcoin hard fork that would allow roughly 79,956 BTC, worth more than $5.2 billion at current prices, to be recovered from a long-dormant address linked to the exchange’s 2011 hack.

The proposal targets the address 1Feex...sb6uF, which received nearly 80,000 BTC following a documented compromise of Mt. Gox’s systems in June 2011. The coins have not moved in more than 15 years, suggesting the attacker may have lost the private keys or has chosen not to move or return the funds.

Under current Bitcoin rules, those funds can only be spent with the corresponding private key.

The proposal says it would "add a consensus rule that allows spending the unspent outputs locked to the theft address using a signature from the Mt. Gox recovery address, so that the funds can be returned to Mt. Gox creditors through the existing court-supervised rehabilitation process."

The draft is framed as a starting point for debate, which Karpelès describes as "an attempt to start a discussion about whether the Bitcoin community considers this specific, exceptional case worth addressing." He also specifies that the rule change would apply only to that single address and would activate at a future block height if adopted by the network.

Arguments for and against

In outlining the rationale, Karpelès describes the theft as "unambiguous," notes the coins have remained inactive for 15 years, and points out that a court-supervised rehabilitation process is already in place to distribute any recovered funds to verified creditors.

He also frames the change as technically limited and narrow, writing that it is a “one-time, hardcoded exception for a specific case with unique characteristics,” not a general mechanism for reversing transactions or recovering stolen funds.

Still, the proposal acknowledges obvious downsides.

Among them is the concern that altering ownership rules for a specific address would set a precedent that could undermine Bitcoin’s immutability. "If it can be done once, the argument goes, it can be done again," the draft states. It also raises the question of who decides which cases merit protocol intervention, noting that other major hacks could seek similar treatment.

The document further concedes that coordinating a hard fork would carry risks, including the possibility of a chain split if parts of the network refuse to upgrade.

Existing Mt. Gox repayments

The coins referenced in the proposal are not part of the assets currently being distributed to creditors.

Following Mt. Gox’s 2014 collapse, roughly 200,000 BTC were later recovered and placed under the control of court-appointed trustee Nobuaki Kobayashi as part of Japan’s civil rehabilitation process. Those holdings have formed the basis of creditor repayments that began in mid-2024.

As previously reported, the trustee pushed the repayment deadline to October 2026, marking the third extension. According to Arkham Intelligence data, the estate still holds 34,689 BTC across its wallets, and past movements, including a 10,608 BTC transfer in November, have typically preceded distributions.