Day Trading for a Living?

Re:Day Trading for a Living? by mruts on Wednesday September 11, 2019 @01:29PM (#20942601)

Okay, let’s do the math buddy. Let’s assume the null hypothesis (the market) has a mean return of 10% and vol of 10%. RenTec’s Medallion Fund has made 80% annualized return before fees in the last 20 years. Assuming the market is a random walk (it’s not), the chance of RenTec making >50% (I don’t think they’ve ever made less than that in 20 years) every year for 20 years is...

3.486 x 10^(-91)

The actual probability is a lot smaller btw.

Why do people keep posting this tired argument over and over? It’s not true. There’s no evidence that it is true. The math strongly suggests (see above) that you can beat the market.

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Re:Day Trading for a Living? by Macross8299 on Wednesday September 11, 2019 @02:56PM (#20943498)

>Why do people keep posting this tired argument over and over?

Sour grapes. Easier to pretend _nobody_ beats the market than honestly admit you're not willing to put in the effort to constantly discover new alpha. And it's fine to not be willing to do that -- it takes a lot of effort and skill to discover alpha and most people will be better off improving their skills in their day job and just tracking indexes.

Doesn't mean it's impossible to beat the market, especially as a small investor where you have some advantages over larger players (your orders aren't large enough to move markets and reveal valuable information)

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