However if your strategies are well known people typically won't pay you much (if anything) to manage their money, because a bunch of shops will be offering comparable results with the same thing.
Continuing with risk parity: there are walkthroughs of how this works with code and math available online: https://cryptm.org/posts/2020/08/01/parity.html
Note the alpha, beta, volatility and Sharpe measures comparing a straightforward risk parity strategy to SPY.
It's not controversial to anyone in the actual industry that you can beat the market on a risk-adjusted basis. Very often the techniques for doing that are well known and can be levered up to safely beat SPY on a total basis with less overall risk. What's truly difficult (and secret) is beating the market by several standard deviations.
I don't know anything about this blog^[0] , but I wanted to find some charts comparing a well known risk parity fund to more general portfiolios. Trusting that they're accurate, it looks like risk parity performed great in 2008, but hasn't beat the market over longer periods of time. Even measuring from 2007 to late 2020, it appears a 60/40 bond fund has beat it substantially.
Thus I'm not really sure what grounds there is to say risk parity beats the market. Certainly not by all measurements. I'm not a huge financial guy though, maybe I'm misunderstanding something?
[0] https://www.evidenceinvestor.com/the-all-weather-portfolio-e...
Sorry, I meant you don't need to find a book, you can find the info online.
The problem for me going forward is that these returns for the last 40 years have been do to falling interest rates. Can the rates keep falling? A little bit more. Will they go negative like some other countries? Maybe? But at some point I have to wonder if this strategy is still viable.
Are there any mutual funds or ETFs which follow it?
This simply isn't true. Sometimes there are dollar bills on the ground. It takes a lot of years for everyone to pick them all up.
Keep in mind that the efficient market hypothesis disproves(TM) starting a successful business just as well as it disproves finding a successful trading strategy. ie: if that were a good startup idea, someone would have already started it, so it can't be an opportunity any longer. EMH is a useful tool but in reality it takes a long time after a fundamental shift creates an opportunity for it to be arbitraged away, and sometimes the opportunity ends due to another fundamental shift, not due to people arbitraging it away.
Keep in mind that changing an investment strategy is simply changing the algorithm used. If I was running a fund returning 7% yoy, and yours was returning 10% yoy, you bet I'd be telling my staff to try out your algorithm.
Magellan was the biggest fund in the world until other funds adopted their innovations and it pretty much reverted to the mean.
https://www.portfoliovisualizer.com/backtest-portfolio?s=y&t...
(Disclaimer: this is not an endorsement)
the downside to this particular fund is the extreme turnover in the fixed income component (only suitable for tax-free accounts) and the interest rate risk; the fund could underperform SPY in a world with increasing interest rates (which is where many traders believe we are now)
Almost all people will immediately balk at the idea of using leverage in investing, despite the higher backward-looking risk adjusted returns. This is especially true when it might be statistically better, but in various stretches (eg. Last March) it does worse.
Any market-beating strategy will no longer work when the market adopts it. I.e. if you have such a strategy, keep it to yourself as long as practical.