Answer: PumpFun bonding curves use massive virtual reserves (typically 30,000 SOL and 1+ billion tokens) that dominate the pricing formula until substantial real volume accumulates, making small sells return effectively zero SOL due to mathematical rounding rather than a technical bug.

Resolutions: (1) Build significant volume through multiple large purchases totaling 10-100+ SOL before attempting sells, (2) use a different DEX like Raydium for immediate buy/sell testing, (3) create tokens with lower virtual reserves if using a custom bonding curve implementation, (4) simulate realistic market conditions with multiple wallets making substantial purchases, or (5) accept that PumpFun is designed for tokens that build community volume over time rather than immediate trading functionality.