The cumulative return to a levered strategy is determined by five elements that fit together in a simple, useful formula. A previously undocumented element is the covariance between leverage and excess return to the fully invested source portfolio underlying the strategy. In an empirical study of volatility-targeting strategies over the 84-year period 1929–2013, this covariance accounted for a reduction in return that substantially diminished the Sharpe ratio in all cases.
Note: Earlier versions of this paper circulated under the title ‘The Decision to Lever.'”