2019 · John C. Bogle / The Bogle eBlog
The Riddle of Performance Attribution — Who’s in Charge Here: Asset Allocation or Cost?
Exhibit I: Source of Variations in Return* Factor BHB Study Vanguard Study Allocation Policy 92.5% 88.7% Allocation Changes and Security Selection 7.5 11.3 Total 100.0% 100.0% _________________ *Average of BHB’s 1986 and 1991 studies; Vanguard study based on ten years ended December 31, 1996. Turning from variations in return to total return, both the pension plans and the mutual funds displayed returns before expenses that fell slightly short of the returns of the market index benchmarks. For the balanced funds, we used the Standard & Poor’s 500 Index for stocks, the Lehman Intermediate-Term Corporate Bond Index for bonds, and U.S. Treasury Bills for cash. (In neither the BHB study nor in our study did the results vary significantly if the all-market Wilshire 5000 Equity Index were used instead of the S&P 500.) What we are witnessing, as has been reaffirmed over what seems like time immemorial, is the failure of active mangers, on average, to outperform appropriate market indexes. Exhibit II: Returns Before Costs BHB Study Vanguard Study Index Composite Return 11.8% 12.5% Fund Composite Return (before costs) 11.2 12.3 Difference -0.6% -0.2% It seems likely that portfolio transaction costs were a material factor in both the pension plan and the mutual fund shortfalls to the unmanaged index portfolio. Undistinguished individual stock selection (or, if you will, highly efficient markets) simply meant that the active manager failed to add value.