diff --git a/doc/optimal_protocol_fee.md b/doc/optimal_protocol_fee.md index 818d14b..243f1f4 100644 --- a/doc/optimal_protocol_fee.md +++ b/doc/optimal_protocol_fee.md @@ -12,7 +12,7 @@ Let: - $v$ = volume (exogenous, constant) - $F$ = total LP fee rate (exogenous, fixed) - $f$ = LP fee share (fraction of $F$ retained by LPs) -- $g$ = protocol fee share (fraction of $F$ retained by protocol) +- $g$ = protocol fee share (fraction of $F$ retained by the protocol) - $r$ = short-term market rate (exogenous, includes risk premium) - $L$ = total value locked (endogenous) @@ -25,7 +25,8 @@ In equilibrium, LP earnings equal the opportunity cost: $$v f = r L$$ Thus: -$$L = \frac{vf}{r}$$ + +$$L = \frac{v f}{r}$$ The TVL adjusts until LPs are indifferent between deploying capital here versus the outside market rate $r$. @@ -33,15 +34,15 @@ The TVL adjusts until LPs are indifferent between deploying capital here versus Protocol profit is: -$$p = fgL = fg \cdot \frac{vf}{r} = \frac{v}{r} f^2 g$$ +$$p = f g L = f g \cdot \frac{v f}{r} = \frac{v}{r} f^2 g$$ Substituting $f = 1 - g$: -$$p(g) = \frac{v}{r} (1-g)^2 g \quad \text{for } g \in [0,1]$$ +$$p(g) = \frac{v}{r} (1 - g)^2 g \quad \text{for } g \in [0,1]$$ -Let $h(g) = g(1-g)^2$. Taking the derivative: +Let $h(g) = g(1 - g)^2$. Taking the derivative: -$$h'(g) = (1-g)^2 - 2g(1-g) = (1-g)(1-3g)$$ +$$h'(g) = (1 - g)^2 - 2 g (1 - g) = (1 - g)(1 - 3 g)$$ ## 4. Solution @@ -50,16 +51,16 @@ Setting $h'(g) = 0$ yields critical points at $g = 1$ and $g = \frac{1}{3}$. Evaluating: - $h(0) = 0$ - $h(1) = 0$ -- $h(1/3) = \frac{1}{3} \cdot \left(\frac{2}{3}\right)^2 = \frac{4}{27}$ +- $h\!\left(\frac{1}{3}\right) = \frac{1}{3} \cdot \left(\frac{2}{3}\right)^2 = \frac{4}{27}$ The maximum occurs at **$g^* = \frac{1}{3}$**, giving: -| Quantity | Value | -|----------|-------| -| Protocol fee share | $g^* = \frac{1}{3}$ | -| LP fee share | $f^* = \frac{2}{3}$ | -| Equilibrium TVL | $L^* = \frac{2v}{3r}$ | -| Max protocol profit | $p^* = \frac{4v}{27r}$ | +| Quantity | Value | +|-----------------------|---------------------------| +| Protocol fee share | $g^* = \frac{1}{3}$ | +| LP fee share | $f^* = \frac{2}{3}$ | +| Equilibrium TVL | $L^* = \frac{2 v}{3 r}$ | +| Max protocol profit | $p^* = \frac{4 v}{27 r}$ | ## Conclusion @@ -73,17 +74,13 @@ Under the assumptions: the protocol’s optimal fee policy is: - **Protocol share of the fee pool:** - \[ - \phi_P^* = \frac{1}{3} - \] + $\phi_P^* = \frac{1}{3}$ - **LP share of the fee pool:** - \[ - \phi_L^* = \frac{2}{3}. - \] + $\phi_L^* = \frac{2}{3}$ Equivalently, in absolute terms: -- **Optimal protocol fee rate:** \(F/3\), -- **Optimal LP fee rate:** \(2F/3\). +- **Optimal protocol fee rate:** $F/3$, +- **Optimal LP fee rate:** $2F/3$. This fee split balances extracting revenue from trades against maintaining sufficiently attractive LP returns to support a large equilibrium TVL. \ No newline at end of file