Measure of interest-rate sensitivity; the weighted-average time to receive a bond's cash flows (Macaulay duration). Modified duration approximates price impact: Δ P ≈ -D_mod · Δ y · P. Floating-rate direct loans have effective duration of only sim 0.1–0.25 years (the time to next reset), which is why direct lending performed strongly through the 2022–2023 rate hiking cycle while fixed-rate high-yield bonds suffered large mark-to-market losses.