The above of course ignores trading costs.
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Browse All TopicsHi Guys,
Image the following Stockmarket Situation (eventhough this might not be a "real/correct" situation)
Known variables:
-Date you buy the stock
-Date you HAVE to sell the stock
-Probability you win a certain amount (and probability you lose everything)
To maximize the winnings over time the "compound-interest-effect"
How do I allocate a certain amount of capital to the different stocks to use the "compound interest-effect" effectively.
Is this a known problem? Is there a general solution?
Please see the attached image for further clarification.
Thank you very very much,
Yours Annegret
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Thank you for your comment:
But as I wrote: I know the probability (thats why I wrote that it might not be a "real" stockmarket situation)
To clarify:
At the time of buying the stock I do know the probabilty (or at least a very close estimation) to win a certain amount at the time (which is fixed) of selling.
Why not invest everything in the "best" stock: to spread the risk and use the "compound-interest-effect"
Please ignore trading cost!
Annagret
If you know the probability distribution of the "gain" at the time of selling then, you can calculate the expected gain of the stock. Integrate g.P(g) where g is the gain. The expected return is the gain/share price. Now this is the metric by which you calculate the best stock.
Every time you have fresh probability data you recalculate the best stock and move all your money there. That is the optimal strategy to maximize the expected value of your eventual return.
A cautionary note: this is maximizing the expected return, there is no awareness of risk. If you wish to factor in risk then you would have to balance risk against potential return in a more complicated calculation.
I dont know if you are after such detail.
As far as the compound interest, again I don't see how compound interest applies here. I can see that the recalculation of the best stock and rebalancing of your portfolio may seem analogous to compounding interest, but that term is generally reserved for fixed or at least predictable interest compounded at a given period.
Hi,
Thanks again!
The term "compound-interest" might not be perfect, but it gets the idea across I hope.
I'm looking for a hint how you might solve the described problem or an (part of) algorithm (with the given variables/facts).
I'm NOT looking for general investment advice or something similar!
Best Regards,
Annegret
Look at the attached picture with an additional example:
Image you are at the "now"-point:
You have invested a part of your money in stock 1and you know that stocks 2-5 might be a good investment each.
Eventhough stock 2 might be the best, remember you might lose everything (for example all stocks are derivatives where you can lose everything) ! This is why you need/should spread you investemnt over several stocks
The question is: what is the best allocation (which stocks gets how much money)?
Just splitting the money evenly between Stock 2 and 3 might be bad, because stock 3 pays out earlier so that you can reinvest your money in stock 4 and so on (under the assumption that stock 2 and 3 are equally "good").
Assuming you have the probability of all possible gains for each stock. i.e. P(+$1.00)=p1 P(+$1.50)=p2 etc.
Then for each stock the expected Gain is either the sum or the integral (discrete or continous) of " Gain * P(Gain)".
Now you need to maximise your return/profit. You therefore want to be fully invested in the stock that has the best ratio of (Expected Gain/ Stock price) at the moment. Statistically this strategy will give you the best expected result. That is over an infinite number of trials this is the best strategy.
As an analogy this is looking at the average (expected return) without considering the standard deviation (a measure of risk).
Presume that all buy & sell time are restricted. Let's try to consider some very special case:
Case 1 - All have to buy & sell at the same time
For this, it is quite similar to finding the efficient frontier for a n-risky asset portfolio. So, you have to consider this :
http://en.wikipedia.org/wi
Case 2 - Only allow to buy stock 1 at time 0
For this, I've no solution yet.... But seems that we can make up of different composition and then try to pick the optimized one ...
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by: wizzardofozPosted on 2009-10-03 at 12:58:52ID: 25486767
The problem in any such system is knowing the probabilities accurately. Your assumption is that you will know the upside and downside risk accurately at any time for the stocks you are monitoring. That assumption does not hold in the real world. Indeed underestimating the risk of defaults was what caused the current collapse. However let us assume that you know the risks accurately at any given moment.
The compound interest effect is not really applicable to this situation because though the investment is fluctuating throughout the day, there is no fixed interest rate.
Your optimal strategy is to be at any point in time fully invested in the stock that has the greatest expected return from that time to the end of the game. So if a stock appreciates considerably and you expect that the return from now to the end of the game is therefore lower, you should move everything to the stock that still has the most expected return.