Eli Ben-Sasson, co-founder and CEO of StarkWare and one of the most cited names in modern cryptography, has kicked off a fresh debate around Bitcoin’s monetary policy after saying the network’s iconic 21 million supply cap simply does not add up in the long run.
In a post on X shared today, Ben-Sasson wrote that “Capping the supply of Bitcoin at 21M doesn’t make sense” because “over time, keys will be lost” and, taken to the limit, “as time goes to infinity, all keys will be lost.”
He clarified that he still supports a clear monetary policy with an absolute upper bound, but through a maximum issuance rate rather than a fixed total supply, floating a figure of around 4% annual issuance tied to global human population growth so that “there is enough to go around.”
Ben-Sasson’s team at StarkWare has worked on quantum-resistant upgrades for Bitcoin and developed post-quantum migration plans for Starknet. He has published foundational papers on scalable zero-knowledge proofs that power multiple blockchain projects today.
The Math Behind His “Lost Keys” Concern
Ben-Sasson’s argument leans on a real, measurable trend. As of early July 2026, roughly 20.05 million BTC have already been mined out of the 21 million cap, leaving fewer than 1 million coins to be issued between now and the year 2140.
However, multiple industry estimates from research desks, including Ledger and River Financial, suggest that 3 million to 4 million BTC are already permanently lost. These are coins locked behind forgotten seed phrases, destroyed hardware wallets, discarded hard drives, and wallets belonging to deceased holders. That means Bitcoin’s effective circulating supply is likely closer to 16 to 17 million BTC, and this attrition never stops.
His point is straightforward. A hard cap does not model the ongoing leakage of coins out of the economy. Over decades and centuries, that leakage compounds.
What He is Actually Proposing
Ben-Sasson is not calling for open-ended inflation, and this is where his framing differs from earlier tail emission discussions in Bitcoin circles.
Instead of a small fixed perpetual issuance, he is suggesting a rate ceiling. Under his framing, Bitcoin would have no fixed total supply but an absolute upper bound on how fast new supply can enter the market, benchmarked at something like 4% per year and pegged conceptually to global human population growth.
In his view, this achieves two things at once. It offsets the natural loss of coins so real usable supply stays roughly balanced against demand, and it gives miners a predictable, ongoing security budget that does not depend entirely on transaction fees post-2140.
The Security Budget Problem He Alluded To
Ben-Sasson briefly referenced “the security problem, looming large on the horizon,” and that is a discussion that has been building inside Bitcoin engineering circles for years.
Today, the block subsidy sits at 3.125 BTC per block after the April 2024 halving. It will drop to roughly 1.5625 BTC after the next halving, expected around April 2028, and continue halving roughly every four years until it effectively hits zero around 2140. From that point on, miner revenue must come entirely from transaction fees.
Bitcoin researchers on forums like Delving Bitcoin have been openly debating whether fees alone can sustain enough hashrate to keep the network economically secure against a well-funded attacker. Ben-Sasson’s rate-capped issuance idea is one answer to that question, though certainly not the only one.
Bitcoin Community Fires Back
The reaction from the Bitcoin side of X was, predictably, sharp. Replies to his post framed the 21 million cap as a non-negotiable foundation.
A recurring theme in the responses was that the cap is Bitcoin’s social contract and that touching it would effectively create a different asset. Others pointed out that Bitcoin is already infinitely divisible down to satoshis, with the Lightning Network enabling even finer accounting, so scarcity concerns from lost coins are addressed at the unit level rather than the supply level. Some replies were shorter and more blunt, calling the 21M number “central to the religion.”
There is also a hard governance reality behind the pushback. Bitcoin’s consensus rules are notoriously difficult to change. Any modification to the issuance schedule would almost certainly play out as a contentious hard fork and face resistance from miners, node operators, exchanges, and long-term holders whose entire thesis depends on the fixed cap. That is very different from an Ethereum-style monetary policy adjustment where the community has repeatedly accepted issuance changes through EIPs.
What this Debate Signals for 2026
The timing is worth noting. More than 95% of Bitcoin’s total supply has already been issued; the security-budget conversation is no longer theoretical, and institutional treasuries are becoming meaningful holders of the remaining float. Long-tail questions that used to feel like a 2100 problem are moving closer.
There is also a small irony worth flagging. Zcash, the network Ben-Sasson helped create, also uses a 21 million hard cap modeled on Bitcoin. His critique here is aimed at the concept itself rather than at Bitcoin as a project, and it is coming from someone whose own work sits inside the same design tradition.
Whether his suggestion sparks a serious protocol conversation or gets filed under “interesting outsider takes” will depend on how the Bitcoin developer community engages with it over the coming weeks. What it has already done is drag a very old debate about lost coins, tail emission, and long-term miner incentives back into public view, this time from a voice that is very difficult to dismiss.
Also Read: Why Michael Saylor’s Strategy Is Selling Bitcoin After Years of Buying
