Answer to whole thread: Depends on the stability of the correlation.
There are two reasons to complicate and mix it up. Automated strategies can achieve maybe ~100% profit in a good year. But the same strategies bundled in a portfolio can make a multiple of that, up to 300% or 400% per year. Profit is here defined as return per required capital.Quote from savagemp5:
If u have a system A with 80% and B with 40%, i'll say discard the 40% and work fully on the 80%.
Why complicate and mix it up ?
===============Quote from jcl:
Theoretically, it should be possible to make money even with a strategy that is not profitable. I don't mean selling it to newbies for $10000, but by using it in a compound system.
Suppose you have two uncorrelated strategies A and B, with A returning 80% profit and B 40% profit. A compound system of both strategies will not return 60%, but likely more than 100% - the whole is greater than the sum of its parts. I think this is commonly known. But surprisingly, this should even work when strategy B is slightly losing, f.i. -10%. As long as it has some negative correlation to the other strategies, adding it to a compound system can theoretically improve the overall return by reducing drawdown.
Has someone already made experiences with compound systems from uncorrelated or negatively correlated strategies and assets? What's the best money management for ....?

Quote from jcl:
Theoretically, it should be possible to make money even with a strategy that is not profitable. I don't mean selling it to newbies for $10000, but by using it in a compound system.
Suppose you have two uncorrelated strategies A and B, with A returning 80% profit and B 40% profit. A compound system of both strategies will not return 60%, but likely more than 100% - the whole is greater than the sum of its parts. I think this is commonly known. But surprisingly, this should even work when strategy B is slightly losing, f.i. -10%. As long as it has some negative correlation to the other strategies, adding it to a compound system can theoretically improve the overall return by reducing drawdown.
Has someone already made experiences with compound systems from uncorrelated or negatively correlated strategies and assets? What's the best money management for such systems - covariance based or optimal f?

I give you a very simple example.Quote from austinp:
Second, a losing strat is a losing strat. It cannot smooth your equity curve in a positive way. The peak highs will be lower and the peak troughs deeper. Who cares about what happens in between?
That's not much different than common assumption to reverse-engineer a losing strat to make it a winning strat by fading. Logical deduction, incorrect assumption in reality![]()

Quote from austinp:
fwiw: I spent two long, full years of my life in the systems writing world, complete with leasing some 3rd party software for $3,000 annually to run computations until the proverbial cows came home. I often had three computers running different variations of the same concept data-mining all night.
To keep things simple, if you add a net-loss strat to any basket of net-win strats, the end result will be worse in all regards. You may have brief periods of lesser drawdown, but you will also have periods of more extreme drawdown when the winning strats naturally draw while the losing strat piles on the losses.
Losing strats are garbage. Period. All of the time and effort expended to create them and any mental attachment to them is wasted. Delete, discard and move on. A silk Prada cannot be made from Iowa sow's ears![]()
It is indeed so. Ralph Vince has analyzed the correlations of a collection of assets over time, and has found that in situations when prices sharply decline or rise, correlation coefficients rise also. This would probably destroy a portfolio of carefully selected uncorrelated components. You need to observe the correlations for detecting a black swan event, and need to keep reinvestment factors well below the theoretical optimum.Quote from bmatthews:
To put a question to jcl, what would be the effect on this portfolio in the event of a major black swan event?
My feelings is that as fear grips the market, rules begin to change,
Correlations knock into line.