sheardocs

Depositors

Premium

Premium is the USDC buyers pay for the round’s calls. It is credited to every share when the auction is finalized, and you collect it whenever you like.

How it accrues#

The vault keeps one running number, the premium index: USDC paid per share since the vault began, scaled by 10¹⁸. finalize_auction raises it by the round’s premium divided by the share supply at that moment.

index += premium × 10¹⁸ ÷ share supply

Your position remembers the index at its last checkpoint. The difference between the two, times your shares, is what you are owed. Every action that changes your shares checkpoints first, so premium always goes to whoever held the shares when it was paid.

Round 1Round 2Round 3Round 4Round 5Round 6Your last checkpointOwed per sharePremium index: steps up when each auction is finalized

owed = shares × (index − your checkpoint) ÷ 10¹⁸

Fractions below one micro-USDC are carried in your position, not lost.

Who earns a round’s premium#

  • Every share that exists when finalize_auction runs, including shares that came in between rounds.
  • Shares with a queued withdrawal. They earn the round they wait through.
  • Not queued deposits. They become shares after settlement and earn from the next auction.
  • Not shares moved in after the auction. The sender keeps what was earned before the move.

Collecting#

claim_premium sends everything you are owed, in whole micro-USDC, to your USDC account. It works in every phase, and nothing expires. The app creates the USDC account in the same transaction if it is missing.

How much to expect#

Each week’s premium is the clearing price times the calls sold. In a vault of 10,000 TSLAx with every call sold at $0.80, depositors receive $8,000, or $0.80 per TSLAx for that week.

Rounding#

The index rounds down, so a few micro-USDC of each round can be left over. That dust stays in the premium account; it is never paid to anyone else and never taken by the program.