Limiting portfolio risk to extreme "black swan" events.

I am not looking for a systematic way to call market tops or bubbles, I don’t think they exist.

I am far more interested in finding ways to limit the exposure on the downside of a portfolio due to “black swan” events. The expression made famous by Nicholas Taleeb in his book The Black Swan. Such events would be defined as

• unlikely events with disastrous circumstances,
• bursting of bubbles, or
• other low probability events that could have disastrous consequences on a portfolio.

Also,  such thing as a perfect hedge that protects the downside and retains the potential for upside gains… is either non-existing or very rare.

http://seekingalpha.com/article/185531-in-search-of-the-illusive-black-swan-hedge-one-idea-worth-trying