Interest rates

One dollar pool lends to many books. Each book has its own rate curve, and suppliers earn the blend.

Borrow rates follow a kinked curve per book. One dollar pool lends to every book, and suppliers earn the blend. Rate today is 6.81%. InterestRateModel is a library, not a deployed contract. Stockline calls it when interest accrues.

A crypto protocol often ships one curve for a pool. Stockline stores IRM params per book so a high-beta name can be more expensive than an index book without splitting the dollar pool.

Aave-style params, already per-second WAD. kink is utilization in WAD. Division rounds up so debt never accrues slower than the curve.

if u <= kink:
  rate = base + slopeBelow * u / kink
else:
  rate = base + slopeBelow + slopeAbove * (u - kink) / (1 - kink)

Param	Launch value
`baseRate`	`1e10` / s
`slopeBelowKink`	`2e10` / s
`slopeAboveKink`	`8e10` / s
`kink`	0.90

The app mock uses 5.4 + 3.0 * u² in app/lib/risk.ts. That formula is display-only. Integrators must use this library, not the mock. Utilization is borrowed / supplied in WAD. Full utilization is expensive on purpose so unused dollars return for withdrawals. Suppliers earn the weighted borrow interest of all books, net of the 15% reserve factor. sUSDG is ERC-4626. The exchange rate rises as interest is paid. Creator-fee donations increase totalAssets without minting shares. A rate is a reading at build, labeled today. It is not a forecast. The kink at 90 percent is the point where the slope steepens. That is why Move to Cash can be instant on a quiet day and delayed when the pool is lent out. Per-book debt uses that book’s borrow index, so a rate change on one book never touches another book’s accrued interest. Do not quote a future rate. The docs and the app both say rate today. The build pulls the demo rate from PARAMETERS.json unless an RPC computes the live curve. Related: Earn, Parameters, Reserve and fees, Books and tiers.

Introduction

Using Stockline

Concepts

Developers

Ecosystem

Resources