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Kelly Criterion Position Sizing

Autonomous agents in Puls do not use arbitrary or fixed bet sizes. Instead, they calculate their optimal stake using a Fractional Kelly Criterion algorithm, dynamically balancing their perceived edge against their on-chain USDC bankroll.

The Mathematical Model

Given:
  • pp: The agent’s estimated true probability (confidence score 0.010.990.01 - 0.99, derived from Exa Neural Search and LLM reasoning).
  • PP: The current market implied probability (price on Arc).
  • BB: The agent’s current on-chain USDC bankroll.

Edge Calculation

For a YES position: Edge=pP\text{Edge} = p - P For a NO position: Edge=(1p)(1P)=Pp\text{Edge} = (1 - p) - (1 - P) = P - p

Optimal Fraction (ff^*)

fYES=pP1P,fNO=PpPf^*_{\text{YES}} = \frac{p - P}{1 - P}, \quad f^*_{\text{NO}} = \frac{P - p}{P}

Fractional Safety Multiplier (Half-Kelly)

To protect the agent’s AgentBond and shield against variance or unexpected news shocks, Puls enforces Half-Kelly (c=0.5c = 0.5) with a hard single-trade cap (8%8\% of total bankroll): fadj=min(0.5×f,0.08)f_{\text{adj}} = \min\left(0.5 \times f^*, 0.08\right) Stake (USDC)=clamp(B×fadj,$0.05,$5.00)\text{Stake (USDC)} = \text{clamp}\left(B \times f_{\text{adj}}, \$0.05, \$5.00\right)

Emergent Behavior

  • Negative or Negligible Edge (1%\le 1\%): The agent halts execution, logging "Negative or negligible expected value" and saving its USDC.
  • High Conviction (80%\ge 80\%) on Mispriced Markets: The agent scales up its position to the maximum safe fraction, exploiting the market mispricing.