First, What Is Compound?
Imagine a bank, but instead of tellers and loan officers, it’s run entirely by code on the Ethereum blockchain. That’s the simplest way to think about Compound. It’s a decentralized protocol where you can deposit your crypto assets and earn interest,
or you can use your crypto as collateral to borrow other assets. Founded in 2017, it became one of the foundational projects of the DeFi movement, creating a permissionless way for capital to flow without traditional intermediaries. The whole system is governed by holders of its native token, COMP, who vote on everything from adding new assets to changing interest rate models.
The Original Promise: Pooled Risk
Compound’s first hugely successful version (V2) used what’s called a “pooled-risk” model. You could deposit a wide variety of assets into one giant pool, and you could borrow any other asset from the same pool. The appeal was flexibility. The risk, however, was shared. Because all the collateral was essentially swimming in the same pool, a single bad asset—one that suddenly lost all its value or had a faulty price feed—could theoretically create a crisis and drain the entire protocol. The system was only as strong as its weakest link.
The Hidden Detail: A Move to Isolated Markets
This brings us to the big change, introduced with Compound V3. On the surface, it was just an upgrade. But underneath, it was a total philosophical shift. Instead of one giant pool, V3 introduced isolated markets. In this new model, each market is built around a single borrowable “base” asset, usually a stablecoin like USDC. You can still supply various cryptocurrencies like ETH or WBTC as collateral, but you can only borrow that one specific base asset within that market. This is the hidden detail: Compound quietly moved from a model of shared, interconnected risk to one of contained, siloed risk. Each market is now its own island, preventing a crisis in one from spreading to the others.
Why This Changes Everything
So, what’s the catch? While this new model dramatically improves security and capital efficiency, it comes with a trade-off that many users might miss. In the old V2 model, the collateral you supplied would earn interest. In V3, it does not. Your supplied assets now function purely as collateral to enable borrowing; they no longer generate passive yield on their own. The purpose of supplying assets has fundamentally narrowed. You’re no longer a lender in the traditional sense, but purely a prospective borrower posting collateral. This change makes the protocol safer by preventing the complex re-use of assets, but it removes a key incentive that drew many early users to the platform. It’s a move from a multi-purpose money market to a more focused and secure borrowing facility, prioritizing safety and efficiency over the broader utility of its predecessor.
