Mutual fund flows generate substantial price impact, amplify fragility, and trigger fire sales. We document a stark contrast for separate accounts—the dominant institutional investment vehicle: their flows generate essentially no price impact, fragility, or fire-sale risk. This pattern holds within mutual fund–separate account twins managed under identical strategies and is not driven by liquidity conditions at the time flows occur. Using trade-level data from a major transition manager, we show that specialized execution intermediaries significantly reduce trading costs and dampen price dislocations. Our findings reveal large heterogeneity in how investor demand transmits to prices—not all flows are equally price-moving.