There was “modern,” then “post-modern”...it’s only a matter of time before “post-post-modern” comes along.
But for now, let’s focus on PMPT: Post-Modern Portfolio Theory.
Regular old Modern Portfolio Theory (MPT) uses the mean variance of investment returns to optimize diverse portfolios. While MPT is considered a huge advancement in portfolio strategy and management, it’s got its limitations. For instance, the reason mean variance is used is because it’s supposed to be a proxy for investment risk. Plus, it has some statistical assumptions of a normal distribution, which isn’t always best. MPT does all right, but, hey...we can always do better, right?
In contrast, PMPT uses downside risk of returns, rather than mean variance, as a proxy for investment risk. For stat-nerds, that means they used the standard deviation of all returns, rather than just for negative returns, to measure risk. Where MPT assumes symmetrical risk, PMPT assumes asymmetrical risk. PMPT was a decades-in-the-making improvement to the revolutionary (but limited) MPT.
Now just waiting on the next iteration: PPMPT.
Related or Semi-related Video
Finance: What is Efficient Markets Theor...141 Views
Finance a la shmoop what is the efficient markets theory well
there should just be a big picture of Warren Buffett right here it should be [Two men carrying a framed picture of Warren Buffett]
the man Warren explaining the efficient market theory himself and that theory
states that it's impossible to beat the market over a sustained period of time
it should be Warren Buffett who explains that all relevant information comes [Warren Buffett giving a presentation on stage]
public in public stocks and that the market more or less immediately
incorporates all that information in its pricing
hence nobody can ever beat the market over a long period of time so why should [Men falling asleep during a presentation]
Warren Buffett be giving this little definition because the efficient market
theory is wrong Buffett has beaten the market for decades in a row in every way [Warren Buffett beating up the market with a stick]
shape and form so you have a really memorable huge figure in finance this
guy and then pipsqueak professors who are kind of a laughing stock whenever the [Professor jumping on the microphone stand trying to talk]
wealthy power crowds gather in Omaha for their National Convention that's what
they say at the Woodstock of Finance if you will fortunately most people keep [Man with arms folded standing naked in a corridor]
their clothes on for this one
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