> For the complete documentation index, see [llms.txt](https://docs.btcd.fi/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.btcd.fi/readme.md).

# Welcome to Bitcoin Dollar

What Bitcoin Dollar is, the tokens it uses, and where to start.

<figure><img src="https://1304119658-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FnIdk11PalG0VB24i5MDQ%2Fuploads%2Ff3AXXTjUKFs3EjOPJe4h%2FBTCD%20Logo.png?alt=media&#x26;token=8e57266f-8df4-4839-96de-7229dc537804" alt="Bitcoin Dollar logo"><figcaption></figcaption></figure>

## What is Bitcoin Dollar?

Bitcoin Dollar (BTCD) has a peg that tracks a portfolio that is half bitcoin and half US dollars. BTCD rises and falls with bitcoin, but by less. Its target price follows the square root of the bitcoin price. For small moves, BTCD moves about half as much as bitcoin in percentage terms. Larger moves are dampened further.

BTCD's reserves are held in bitcoin and dollars. An automated system, the engine, manages them. It values the reserves, keeps them close to 50/50, invests them in on-chain yield strategies, and pays surplus to stakers as yield. If the reserves ever fall short, every BTCD is priced at what the reserves actually back, so no holder gains by leaving first.

Bitcoin Dollar is developed by BTCD Labs.

## The tokens

| Token     | What it is                                                                                                                                                  |
| --------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **BTCD**  | The base token. Anyone can buy, sell and hold it; a Uniswap v3 USDC/BTCD market is listed below. Whitelisted partners mint and redeem it at the fair price. |
| **sBTCD** | Staked BTCD. Yield is paid into the sBTCD vault, so each sBTCD represents more BTCD over time.                                                              |
| **FISC**  | The governance token.                                                                                                                                       |
| **bdUSD** | The receipt token of the USD Vault (USD Growth). Dollar yield; BTC exposure nets to zero.                                                                   |
| **bdBTC** | The receipt token in the proposed BTC Vault design. See [BTC Growth](/opportunities/btc-growth.md).                                                         |
| **BTCdc** | The receipt token of the wBTC Carry Vault.                                                                                                                  |

## The mental model

If you understand Ethena, you already understand the shape of Bitcoin Dollar:

| Ethena | Bitcoin Dollar | Role                         |
| ------ | -------------- | ---------------------------- |
| USDe   | BTCD           | Base collateralized token    |
| sUSDe  | sBTCD          | Yield-bearing staked version |
| ENA    | FISC           | Governance token             |

The difference is the peg target. USDe targets one US dollar. BTCD targets a portfolio that is always about 50% bitcoin and 50% dollars, so the BTCD peg moves with the bitcoin price at roughly half the volatility of holding bitcoin outright.

## Quick start

* **Hold BTCD.** Buy it on the market, including the [Uniswap v3 USDC/BTCD pool](https://etherscan.io/address/0x81b5d56A6fe73e4cA9C2201Aa2d5B366cd6e14dc).
* **Stake BTCD.** Deposit BTCD into the sBTCD vault and receive sBTCD.
* **Unstake.** Redeem sBTCD for the underlying BTCD.
* **Earn in dollars.** Deposit USDC into the [USD Vault](https://app.ipor.io/fusion/ethereum/0xf8f226da66244f89e70c5b5d1a5c5b0d505eb1d8) and receive bdUSD. See [USD Growth](/opportunities/usd-growth.md).
* **Lend wBTC.** Supply wBTC to the [Morpho market](https://app.morpho.org/ethereum/variable/0xc89db30f2cf64a953e99eff269246cb5454e7b023ca21db2edfa69abac08c988/wbtc-wsbtcd) the USD Vault borrows from. See [BTC Prime](/opportunities/btc-prime.md).
* **Explore the BTC Vault design.** See [BTC Growth](/opportunities/btc-growth.md) for the proposed bdBTC vault.
* **Mint or redeem at the fair price.** Verified business partners use the RFQ desk. See [Minting, redemption and peg keeping](/how-the-engine-works/minting-redemption-and-peg-keeping.md).

## Where to start reading

Bitcoin Dollar introduces a few ideas that the rest of these docs depend on. Read these first:

1. [The 50/50 peg](/readme/the-50-50-peg.md)
2. [Omega (ω): the language of exposure](/readme/omega.md)
3. [How the engine works](/how-the-engine-works.md)
4. [Opportunities](/opportunities.md)
5. [Transparency and verification](/transparency-and-verification.md)

The 2 November 2026 liquidity check found BTCD in the Uniswap v3 pool linked above and no reserves in the identified Curve BTCD/USDC pool. Pool balances change; this is a dated venue observation, not a trading-volume ranking.