Deposits and redemptions on tBTC are managed in lots. To make the system rational and manageable, deposit and redemption lots must be selected from one of a set of fixed sizes, managed by the system. For ease of demonstration, we have often used the example of a 1 BTC lot size — but tBTC is not intended in any way to exclude based on wealth. That is why tBTC will immediately support lot sizes as low as .001 BTC.

Over time, we will add new lot sizes and adjust them based on user feedback. But the key point will not change: tBTC is for everyone, and no one will be excluded because of a lack of funds.

The reason for standard lot sizes is to ensure that deposits are always redeemable. If users could deposit any amount of BTC, it would be difficult to match redemption orders with specific existing deposits. If everyone is required to deposit BTC in fixed lot sizes, there should always be a deposit of the appropriate size that can be redeemed. This is one of the features that allows tBTC to be flexible and to be a true stablecoin fully backed 1:1 by Bitcoin.

If a depositor wants to deposit a larger amount of BTC than supported by existing lot sizes, they can create multiple deposit requests and fund multiple deposits. This allows for each deposit to be backed by a different signing group, which both simplifies the bonding of signing groups and insulates the wider system against isolated signing group failures, malicious or otherwise. So using the system of lot sizes, users can deposit essentially any amount of Bitcoin they wish. You can read more about how lot sizes work in tBTC’s technical system overview. Note that the overview uses the example of a fixed 1-BTC lot size for ease of explanation — but tBTC currently uses many interval lot sizes ranging between 1 BTC and .001 BTC.

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