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SAM SAM Docs

Withdrawals

When you redeem, SAM burns your shares at the current price and returns the underlying. The design goal is that the vault is always redeemable, you can get out any time, down to the last unit.

What you receive

Section titled “What you receive”

Burning s shares yields (before the withdraw fee):

amount=⌊s⋅CS⌋\text{amount} = \left\lfloor \dfrac{s \cdot C}{S} \right\rfloor

where C is total_coin_in and S is total shares. This is your pro-rata slice of the pool. The withdraw fee (0.01%) is then taken from it.

Where the money comes from

Section titled “Where the money comes from”

SAM serves your redemption in two layers:

  1. Idle buffer first. The liquid balance covers your withdrawal up to whatever it holds: instant, no protocol interaction.
  2. Protocols for the rest. If your withdrawal is larger than idle, the remainder is pulled from the lending protocols.

Because a slice of the vault is always kept liquid (the idle buffer, default 5%), small and medium withdrawals are served entirely from idle.

How the protocol portion is split

Section titled “How the protocol portion is split”

The amount pulled from protocols is spread so it drains the most liquid, lowest-yielding positions first, leaving the high-yielding capital working as long as possible. Each protocol’s pull-weight is:

weighti=availablei∑javailablej⋅1APRi\text{weight}_i = \frac{\text{available}_i}{\sum_j \text{available}_j} \cdot \frac{1}{\text{APR}_i}

Higher available liquidity raises the weight; higher APR lowers it. SAM then makes a first pass assigning each protocol its weighted share (capped by what it can actually return), and a second pass that greedily covers any shortfall from protocols with spare liquidity, so the full amount is always gathered as long as the liquidity exists.

After serving you, if the idle buffer was drawn down, SAM tops it back up from any remaining protocol liquidity, so the next withdrawer is also served instantly.

Always redeemable, down to the last unit

Section titled “Always redeemable, down to the last unit”

Two safeguards make full redemption robust:

  • Rounding drift is absorbed. Over time, tiny rounding differences accumulate between the vault’s accounting and what the protocols can physically return. On a withdrawal SAM caps the protocol-sourced amount at what is actually available, absorbing dust-level drift instead of failing. (A genuine liquidity shortfall far beyond rounding still stops the withdrawal rather than over-paying.)
  • Redemption never over-pays. You can only ever receive the value of the shares you burned, capped by real available liquidity. There is no path to withdraw more than your shares are worth.