Portable Alpha
解释了主动投资经理如何通过市场暴露（贝塔）和选股技能（阿尔法）两种方式获取收益，并探讨了将阿尔法与贝塔分离后应用于其他投资组合的“可转移阿尔法”策略及其优缺点。
Active investment managers provide two types of return: the return from market exposure (or beta) and the return from selection skill (or alpha). Active beta returns typically come from market timing?increasing market exposure in up markets and reducing it in down markets; passive beta returns come from index fund exposure. Alpha comes from security selection within an asset class, so the value that stock-picking adds does not depend on the direction of the market. A true stock-picker, that is, would have a beta of 1.0 relative to the market benchmark, and all value-added would come from active risk or stock-picking. ?Portable? alpha may be achieved by separating the alpha from the beta and then applying it to other portfolios. Investors can obtain portable alphas through traditional long-only strategies. There are benefits and drawbacks of implementing portable alphas in a variety of investment scenarios.