Rather than attempt to adapt Taleb’s distinctions to bond investing, I’m just posting a link to his paper. http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1669317 But the problem of ‘merely robust’ vs. “genuinely anti-fragile’ is at the heart of what I’m experimenting with with my talk of the need to be willing to get short if/when conditions warrant. If calculus is where you and math parted company, don’t let the paper scare you. Enough of it can be understood even if the math isn’t, and the ‘enough’ amounts to this. The sort of "defensive robustness" supposed created by following the guidelines of Modern Portfolio Theory in building portfolios (and, hence, the ability to sustain a lot of damage in market downturns and then recover from it) doesn’t work when the distresses are both unlikely and catastrophic, aka, Black Swan events, not merely normal reversals and corrections. The MPT crowd swears such events don’t occur often enough to worry about. But history proves otherwise, and the math of the paper (and in his others) lays out why the sample of rare events cannot be used to predict their non-occurrence. While all of this might seem like irrelevant theory, the practical consequences are huge. Are you really willing to bet that your portfolio, as presently constructed, will survive another couple of years like 2008-2009 and, furthermore, that they won't happen? I’m not. Even though by the middle of 2009 I had recovered every penny of what I had lost in the prior months and then went on in subsequent months to make some truly fabulous money, I can’t depend on being able to recover a second time if/when another downturn occurs. In other words, I’m willing to bet that attempting to be 'robust' won’t offer enough protection and that becoming ‘anti-fragile’ (so that a market downturn creates profits, rather than takes them away) is the smarter bet. That's the high-level strategy. The low-level stuff, the tactics, are going to vary according to each person's interests, needs, and abilities. But their common theme should be this: "Don't give back your profits. You earned them. Now figure out a way to hang onto to them, no matter what the crazy market does."