Active bond mutual funds are emerging as early warning indicators in the current rising rate environment, with smaller funds showing significant September losses. Market participants are monitoring these underperformers for potential liquidity or structural issues that could precede broader market stress. While major asset managers like Pimco and Fidelity carry greater systemic weight in any deepening bond selloff, smaller active funds typically surface problems first. Investors are tracking the worst-performing funds this month to gauge underlying vulnerabilities within the fixed-income sector as rates continue to climb.