Hubble Protocol

Hubble Protocol is a Solana lending protocol that lets you lock up crypto and borrow USDH, its own dollar stablecoin. This kind of loan is called a collateralized debt position, or CDP: you deposit more value than you borrow, and the loan has no end date. Hubble launched on Solana in January 2022 and accepts SOL, ETH and liquid staking tokens as collateral. Its HBB token is used for governance.

Hubble's USDH is not the USDH on Hyperliquid. That coin comes from a firm called Native Markets and went live in September 2025. It is backed by cash and short-term US Treasuries. Hubble's USDH is backed by what users lock in Hubble on Solana.

Hubble is small today. In 2022 its team also launched Kamino Finance KMNO$0.037+12.2%, which has since grown far larger. The live borrowing and staking figures sit in the widgets on this page.

How Hubble Protocol borrowing works: USDH loans, LTV and fees

To borrow on Hubble, you deposit collateral into a vault and mint USDH against it. You repay whenever you like, because loans have no fixed term. The most you can borrow depends on the vault. Hubble's docs give a range from 80% loan-to-value or lower for volatile assets up to 97% for Kamino kTokens. The main vault, called the DeFi Treasury, takes SOL, ETH, mSOL, stSOL and daoSOL.

Loan-to-value (LTV) is the share of your collateral's worth that you borrow. Hubble's docs explain it with an example: a 125% collateral ratio equals 80% LTV. At 80% LTV, $1,000 of SOL backs $800 of USDH. If SOL falls and your loan reaches the vault's maximum LTV, the loan can be liquidated. To stay safe, add collateral or repay some USDH.

Hubble charges two kinds of fee:

• A minting fee, added to your debt each time you borrow. It varies by vault. The borrowing-fee page uses 0.5% in the DeFi Treasury as its example.
• A stability fee, which works like an annual interest rate. Hubble's docs say the main vault charges 0% in its current form. The rate is set per vault, and riskier assets are meant to pay more.

That pairing is why older reviews call Hubble "0% interest" borrowing. The 0% is the current setting, and the vault rate can change.

Hubble's collateral list includes liquid staking tokens such as mSOL from Marinade MNDE$0.024+0.5% and stSOL from Lido. A liquid staking token keeps earning staking rewards while it sits in your loan. To exit, loan auto-close takes a flash loan, repays your USDH debt, swaps part of your collateral to USDH on Jupiter JUP$0.261+4.6% and returns the rest, all in one transaction.

USDH stablecoin peg: the Peg Stability Module and USDC swaps

USDH aims to stay worth $1. Hubble's main peg tool is a Peg Stability Module (PSM). The PSM lets anyone swap between USDH and USDC at a fixed rate. Minting USDH with USDC is free. Redeeming USDH for USDC costs 0.5%.

Those fixed swaps give traders a cheap way to profit when USDH drifts from $1, and their trades push the price back. Hubble can also raise or lower stability fees and the yield paid to USDH stakers to change demand.

Hubble's docs say the peg has been "remarkably stable" since the January 2022 launch, despite turbulent markets. That is the project's own assessment.

The PSM also changes what backs USDH. USDH started as a coin backed by volatile crypto. When you mint USDH by depositing USDC, that USDC backs the new USDH, so part of the backing can depend on Circle.

Hubble USDH Vault (formerly Stability Pool) and liquidations

The USDH Vault, which Hubble used to call the Stability Pool, is where you stake USDH to help clear bad loans. In return, you earn discounted collateral from liquidations and a variable yield. There is no minimum deposit and no lock-up, so you can withdraw at any time.

Hubble runs a hybrid liquidation model:

• In the original vault, staked USDH repays the debt of a failed loan. Stakers receive that loan's collateral at a discount of about 10%. Their USDH is burned, but they get more value back in collateral.
• For newer assets, outside bots sell the collateral on the open market and keep most of it. Vault stakers still receive a share, and they lose no USDH in the process.

The variable yield is called Hubble Native Yield. It is paid from stability fees, so while the main vault charges 0%, there is little fee income to pass on. Only staked USDH earns it. Holding USDH in your wallet earns nothing.

HBB token: governance, voting and the original fee share

HBB is the token you use to vote on how Hubble Protocol is run. Before you trade it, check the mint address on Phantom's token page, because other tokens use similar names. The widgets on this page show its live price and supply.

Hubble's governance rules let holders with at least 0.5% of voting power propose changes, and holders can delegate their votes to someone else. Each proposal gets a week of voting and debate. The same page says Hubble "will begin as centrally controlled" and hand power to the community slowly.

At launch, HBB was also sold as a way to share in fees. A 2022 CoinCodex review said stakers would get 85% of the fees. Hubble's docs today do not mention that split, and the fees themselves have changed since. That figure describes the 2022 design.

Hubble Protocol and Kamino Finance

Kamino Finance started life as a Hubble product. In August 2022 Hubble launched Kamino to help people who lend their tokens to Solana trading pools. Kamino gives you a kToken as a receipt. Hubble takes kTokens as collateral and lets you borrow more against them than against any other asset.

Kamino has since become a full lending app with its own brand. It is now far bigger than Hubble. Some tools are shared. The Hubble audits repository holds files on Scope, a price-feed program first put out under Hubble's name. Its developer kit is now published as Kamino's Scope SDK.

The link matters to you in two ways. If you hold kTokens, you can borrow USDH against them. And Kamino keeps adding new products, while Hubble's last planned upgrade has not shipped.

Who should use Hubble Protocol

Hubble suits long-term holders of SOL or a liquid staking token who want a dollar loan with no end date and no interest at today's 0% setting. Use it only if you will watch your collateral ratio, since there are no fixed payments to remind you.

The USDH Vault suits USDH holders who are comfortable taking liquidated collateral instead of a fixed yield.

Hubble is a poor fit for three groups:

• People who want to borrow USDC or SOL. Hubble lends only USDH, so you would need to swap and pay the cost.
• Anyone who needs deep USDH liquidity. USDH is a small stablecoin, so large swaps can move its price.
• Users who want an actively developed protocol. The Hubble 2.0 upgrade announced in January 2024 has not shipped.

Is Hubble Protocol safe? Audits, upgrade keys and USDH risks

Hubble Protocol has had outside audits and has run since its launch. But its dated audits are all from its first months, and the plan to lock the code has not shipped. Hubble's docs list five security reviews:

The docs do not say which program or version each review covered. Sec3 is listed as an ongoing reviewer, but Hubble's audit files on GitHub hold no Sec3 report. The OtterSec and Offside Labs files there are named for Scope, the price feed. They do not cover the borrowing program.

The bigger question is who can change the code. The Hubble 2.0 plan promised to lock it so no one could. Hubble has not said that this happened. Its docs also do not say who holds the power to upgrade the Hubble Borrow program: one key or a group of signers. This profile has not checked that on-chain. Treat the program as one that can still be changed until Hubble shows otherwise.

Hubble's risk page names two dangers: a bug that a hacker exploits, and USDH slipping below a dollar. Three more are worth knowing:

• The 0% stability fee is a vault setting, so it is not locked in.
• USDH minted with USDC leans on Circle, the company behind USDC.
• The protocol is small. DeFiLlama shows far less money locked in Hubble than in 2022. A small protocol can mean thin USDH markets and fewer liquidators when prices fall fast.

Hubble Protocol alternatives for borrowing on Solana

For most borrowers, Kamino Finance is the main alternative. Kamino lends several tokens, including USDC, and takes more kinds of collateral. Its markets are much bigger. You pay an interest rate that moves with demand, instead of Hubble's one-off fee.

Hubble's edge is narrow. You get a loan with no end date, no interest at today's settings, and a dollar coin backed by crypto. If you want USDC, or you care more about deep markets than a fixed fee, Kamino is the easier choice. If you want a crypto-backed dollar and plan to hold the loan for a long time, Hubble still does that job.

Hubble 2.0, funding and team

Hubble 2.0 is Hubble's plan for its next stage, posted on X on 3 January 2024. The post said Hubble would run by itself and its code would be locked for good. It would also take more kinds of collateral and buy back HBB automatically. Hubble's docs still show the old vault design, and no launch date has been given.

Marius Ciubotariu and Thomas Short founded Hubble, according to Decrypt.

In September 2022, Multicoin Capital led a $5 million round. The Block reported that this took Hubble's total to $15 million. Other backers include Delphi Digital and Jump Capital.

A Hubble contributor presented the protocol at Breakpoint in 2023, covered in our Breakpoint 2023 Hubble Protocol talk summary.