The distinction between short-term bill purchases and traditional QE hinges on duration extension. Currently, Fed bill purchases remain concentrated at the very short end of the curve—highly temporary interventions. But here's the critical question: once these purchases migrate across the maturity spectrum, progressively shifting from 3-year to 5-year to 7-year instruments, does the policy framework fundamentally transform into QE? The answer isn't semantic—it reflects a shift from liquidity management to sustained balance sheet expansion. When duration extension becomes the primary mechanism, you're no longer just stabilizing overnight funding; you're reshaping long-term rate expectations and money supply dynamics. That operational shift matters for anyone tracking monetary cycles and their downstream effects on risk assets.