The Foundations of Money Management
I
 People
have always wanted to win at the stock exchange. But the
existing industry of attracting money to the market with
promising-named books, metastocks and finams of all kinds
exploits our common prejudices, making us seek wrong things at
wrong places. We're busy looking for a "magic" indicator or
trading system that will keep us winning 90% of the time.
I've found such a system. With numerous tests it almost
never had under 90% profitable trades. The results of one such
a test are given in Table 1 in Omega Research TradeStation
format. The code for the system is in Appendix 1; you may copy
it to Omega TradeStation or SuperCharts and go along winning
(in the sense they usually mean winning, that is, having a
profit on most trades). The system's main secret is a
pseudo-random number generator (too "pseudo" in TradeStation,
but doesn't matter much). Then it all goes as usual: if the
position is profitable, close it. If the market goes against
us, turn investors. Having enjoyed working and socializing
with customers of two brokerages over a couple of years, I can
insist that is just what most traders do - except the fact
they formally replace the random number generator with
analytic forecasts, indicator signals, the neighbor's opinion
in the pit or just a momentary impulse. The problem is that
winning at an exchange and earning money at an exchange are
far from being the same.
Surely, the profit seen in the Table 1
example is casual, a result of a lucky dice roll, whereas it
would not be profitable in most cases. But if one changes the
system entry parameters to more reasonable levels, i.e. sets
mmstp=1, pftlim =4, maxhold =10, this will make the system
profitable in most tests.
So exploiting the principal
idea of speculation - close losing trades fast and let profits
grow - combined with money management allows to earn money
even from random trades. Most people act just opposite to this
principle; they let losses grow, hoping the market turns and
proves how right have they been, and quickly close their
profitable positions to prove how right they're at the moment.
Most beginners and many self-styled pros, as our experience
shows, are sure that the skill of market forecasting equals
the ability to earn money at the market. Getting a profit on a
given trade for them means proving their prognostic abilities
and, consequently, their skill in making money.
A person unfamiliar with trading as a
business could be puzzled by the fact that "successful
investing and trading have nothing in common with
forecasting"*. There is bad news and good news. The bad news
is: markets cannot be prognosed. The good news is: one doesn't
need to do that to have profit. We are concerned not with
getting a profit on every trade, but on making large sums when
we're right. The number of profitable trades may in this case
be less than losing, that is, it is possible to use
worse-than-random forecasting!
As a famous trader Paul
Tudor Jones said: "I may be stopped four or five times per
trade until it really start moving". That is, Paul may win
only on a measly 20-25% times! Yet he'd had three-figure
(percents) of income in five consecutive years with very low
capital corrections1. Almost 100% of Steve Cohen's very large
profits are taken off 5% of trades, and only 55% of his trades
are profitable at all. Despite that in the last seven years
he'd made 90% per year on the average, and had only three
losing months (the worst losses were -2%)2.
The widely used by professional methods of
trend following, as a rule, bring about 30-40% of profit.
Profits or losses in any given trade do not matter - as long
as the amount of money earned per average trade is positive.
This value is called mathematical expectancy. The mathematical
expectancy equals the sum of products of profit probabilities
minus the sum of products of losses probabilities, multiplied
by the losses' size
Simplified, the expectancy may be estimated
as the probability of profits multiplied by the average profit
minus probability of losses multiplied by the average loss. In
terms of the Omega Research TradeStation this looks like:
 Table1.
| Total
Net Profit |
$562.70 |
Open
position P/L |
($75.60) |
| Gross
Profit |
$1,269.40 |
Gross
Loss |
($706.70) |
| Total
#of trades |
276 |
Percent
profitable |
92.75
% |
| Number
winning trades |
256 |
Number
losing trades |
20 |
| Largest
winning trade |
$54.90 |
Largest
losing trade |
($126.50) |
| Average
winning trade |
$4.96 |
Average
losing trade |
($35.33) |
| Ratio
avg win/avg loss |
.14 |
Avg
trade (win &loss) |
$2.04 |
| Max
consec.Winners |
39 |
Max
consec.losers |
2 |
| Avg
#bars in winners |
1 |
Avg
#bars in losers |
17 |
| Account
size required |
$177.30 |
Return
on account |
317.37% |
In a newsgroup discussion one follower of
Elliott's theory said: "Market is no gambling - we make no
bets". Not being an Elliott adherent, for whom everything is
pre-arranged, we do make bets. Since the result of any trade
is unknown, any trade is a bet where we win or lose a certain
sum. The principal difference between gambling (betting) and
market trades (speculations) is first, that gambling creates
its own risks and speculations re-distribute the risks already
present on the market; second, the on a market a trader is
able to provide himself with a statistical advantage, that is,
a positive expectancy.
Let us review betting on a color when playing
roulette. There are 18 red sectors, 18 black and the zero. The
expectancy of winning for a single bet on a color is 18/37 -
(18+1/37) = - 1/37. On the average the house wins from a
single gambler this amount multiplied by the bet size. Despite
the fact some gamblers may win a lot, it is the house that
wins always - because of the biased expectancy, not because
the dealer knows where the ball stops.
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Appendix 1. A
system giving over 90% profitable trades.
{********************************************************* Random
System ¹1. Copyright (c)2001 DT Parameter values
by default: mmstp =1,pflim =4,maxhold
=10 **********************************************************} Inputs:
Bias(.025), {Random entry parameter} mmstp(100),
{Stop loss parameter} pflim(.1), {Profit target
limit} maxhold(50); {maximum holding
period}; Var:Trigger(0),Signal(0),ATR(0),num(1); trigger
=random(1); if trigger < bias then signal =
-1; if trigger >1 - bias then signal =1; ATR
=XAverage(TrueRange,50); { Random Entry} If signal
=1 then Buy("Random_Mkt.LE")num contracts next bar at
open; If signal =1 then Sell("Random_Mkt.SE")num
contracts next bar at open; { Standartized
Exits} if marketposition >0 then begin ExitLong
("MM.LX")Next Bar at EntryPrice -mmstp*ATR
stop; ExitLong ("Pt.LX")Next Bar at EntryPrice
+pflim*ATR limit; if barssinceentry >=maxhold
then ExitLong ("Hold.LX")at close; end; if
marketposition <0 then begin ExitShort
("MM.SX")Next Bar at EntryPrice +mmstp*ATR
stop; ExitShort ("Pt.SX")Next Bar at EntryPrice
-pflim*ATR limit; if barssinceentry >=maxhold
then ExitShort ("Hold.SX")at
close; end;
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Appendix 2. The
simplest system number 2. {************************************************************* The
Simplest System ¹2. Copyright (c)2001
DT **************************************************************} Input:Price((H+L)*.5),PtUp(4.),PtDn(4.); Vars:TrendLine(C),LL(99999),HH(0),num(1); if
MarketPosition <=0 then begin if Price < LL
then LL =Price; if Price cross above LL +PtUp *.001
then begin buy("Simpl.LE ")num contracts next bar at
market; HH =Price; end; end; if
MarketPosition >=0 then begin if Price >HH then
HH =Price; if Price cross below HH -PtDn *.001 then
begin Sell("Simpl.SE ")num contracts next bar at
market; LL =Price; end; end;
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Appendix 3. Data
output to a file to compute mathematical
expectancy {************************************************************* Expectancy
Output Copyright (c)2001
DT **************************************************************} Var:RMult(1),R1(1),Trades(0); Trades
=TotalTrades; R1 =PctUp *.001
*BigPointValue; RMult =PositionProfit(1)/R1; If
barnumber =1 then print(file("D:\TS_Export \M
trading.csv"),"Qty",",","Profit",",","Initial
Risk",",","R multiple"); If Trades <>Trades [1
]then print(file("D:\TS_Export \M
trading.csv"),Num:10:0,",",PositionProfit(1):10:4,",",R1:10:4,",",RMult:10:4);
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To be just we should mention that it is
possible to create a "gambler's advantage" - so a
mathematician Edward Thorp has developed strategies with a
positive expectancy for playing blackjack, which he'd
successfully used in Las Vegas gambling houses. When they
stopped letting him in, he published his methods1, after which
blackjack rules had to be altered to remove the gambler
advantage. In late sixties Thorp took interest in shares
market and became a manager for a private investing
partnership: " Our significant rival then was a Harry
Markowitz, a future Nobel prize winner. After 20 months we had
+39,9% profit compared to Dow Jones' +4,2%. Markowitz went
negative in a couple of years, and we're satisfied with our
stable results… about 20% yearly (standard deviation around
6%0 and zero correlation with the market".
The market allows to play games with a
positive expectancy. This is a necessary condition for
successful stock trading. Actually, as Ralph Vince says, "it
doesn't matter how negative or how positive; only positive or
negative matters". A doubtful claim from our point of view; a
larger positive expectancy is superior to a smaller one.
Besides expectancy, most traders have
problems understanding risk. For instance, a historian by
education, (former) head of a regional investing company with
assets over a million dollars by summer 1997 was sure that
"risk doesn't exist so it cannot be measured" and also sure
that "one shouldn't sell shares at a loss". What can one say
about amateurs then… Risk does exist and it can be measured.
It is considered that risk is a volatility measured as the
standard deviation of the changes of actives traded. This
holds true for investing risk, speculative risk is more
adequately defined as standard deviation of capital changes.
By both those definitions risk is heavily underestimated.
According to Murphy's laws, the worst is yet to come; We shall
employ the following definition: risk is the amount of money
we are ready to lose before withdrawing from a losing trade.
Before opening a position it is necessary to
define the point where we close the position wit a loss to
save capital - the so-called stop loss1, or where we open an
opposite position, having made sure of our mistake concerning
the market direction - the so-called stop-and-reverse. The
difference between the entry point and the stop loss point
multiplied by the number of lots is the starting risk or 1 R2,
independent of how and in which units we measure the stop
level, be it dollars, percents, volatility units or six-packs.
This definition of risk is not equal to the first definition -
the risk may be many times the 1 R if the stops are not
executed due to lack of discipline3, gaps against the position
or unexpectedly high slippage. The profit, then, can be
defined in units of risk per share or in multiples of R. In
terms of multiples the basis rule of speculation will be
formulated as: keep losses at the level of 1 R as long as
possible and let profits reach many times R.
The expectancy in multiples of R will mean
how much can we win or lose per unit of risk in an average
trade. To calculate expectancy in terms of multiples of R we
must place the results of our trades in a table with the
following columns:
| Number
of lots |
Profit
or Loss |
Starting risk |
Multiple of
R |
The Profit or Loss must take into account
broker commissions and slippage. Multiple of R is calculated
by dividing the second column by the third. Then to calculate
expectance it is enough to add up the values of the fourth
column and divide by the number of trades. This method is also
works with "intuitive" trading.
So, we do have a winning strategy - what
next?
We can open a brokerage account and bet all
our capital with the maximal leverage.
Here the most important thing - the money
management begins. To clear the situation here is a pair of
facts. Ralph Vince invented a game, where bet size was the
only moveable parameter. He chose forty doctors of sciences
(i.e. not the dumbest people at least) as players, none of
which were professional traders or studied statistics. The
doctors played a game where 100 random trades were generated,
one by one. Every one began at $1000, and before every trade
one had to make a single decision - how much (up to 50% of the
capital) to bet. 60% of the time the players won their bet,
and 40% of the time they lost their bet. This game has an
expectancy of 20 cents per dollar risked, i.e. in the long run
the player can receive 1 dollar 20 cents per dollar. The
academicals made their 100 bets, enough to resolve the
expectancy. Making the same trades, they finished the game
with different results. Guess how much of them increased their
starting capital? Two of forty. 95% of doctors lost money
playing a game with a positive expectation!1
Van Tharp made an even more striking example.
In an Asian Tour for Dow Jones Telerate TAG (Technical
Analysis Group) he gave lectures in 8 cities before 50-100
listeners each time, most of them professional traders for
large companies or banks that traded shares, bonds or exchange
rates on Forex. In an analogous game over a half of highly
professional traders lost!2 Another personal example - a
trader offered a similar game to a friend employed by Charles
Schwab as a leading analyst. At the first level the
distribution of multiples of R with an expectancy of 0,45 and
60% profitable trades. To get to the second level one had to
make 50% profit in 100 trades. The result was "I cannot get to
level 2 in a day!"3. In 1991 Brinson, Singer and Beebower
published a research of the efficiency of 82 portfolio
managers in a 10-year period, which showed that 91,5% of all
profit was generated by asset distribution3. The asset
distribution meant the division of capital between cash,
shares and bonds. Only 8,5% of profit was due to buying and
selling the right stocks and bonds at the right time.
Let us play the game described by Vince. If
there was no risk, i.e. we knew the result of each trade
beforehand, it would make sense to bet all the capital each
time. So every player would have gained $1000 ..(1.2
^100)=$82,817,974,522.01 .
In reality, if we bet all $1000 on the first
trade, we have a 40% risk to lose all at the first attempt.
Even if we win and have $2000, betting all on the next trade
would be exactly as insane.
Now suppose we bet $200 at a time. So if five
first trades are losing, we again lose all. The probability of
such an event is small, just over 1%. But are we ready for
such a "small" risk, if we can lose all the money? Suppose we
lose in the first two trades (16% probability), so we'd lose
40% of the capital. Beginning from the next trade we must
gather 67% of profit just ot restore the starting capital.
This effect is called "asymmetric leverage"5.
Table 2 shows that loses of over 50% need
improbably large profits just to recover; so if we risk
relatively large sums and lose our chances to end up wit a
profit are negligible.
The result in the doctors' case is explained
not only by oversized bets. A widely spread pitfall is
so-called "gambler's error": People tend to suppose that after
a series of losses the probability of a profit increases, so
we raise our bets. But in this game the probability is not
affected by previous results and always remains at 60%.
Suppose that we bet a certain percent of our
capital and record the current capital after each trade.
Repeat the 100-trades sequence again and again, and after a
lot (1000 or so) series we'll be able to estimate the
distribution of results. Evidently, we'll have different end
profits, since the game is random-based. This is called Monte
Carlo modeling.
Let us arrange the 1000 profit performances
from 1000 series from smaller to larger. Then let us divide
this range into 100 parts with equal number of variants in
each - so every such a percentile will have 10 variants of
performance. The first percentile will contain 10 worst
results, and its top limit (number 10) will correspond to what
they usually formulate as: "In 1% of cases the results will be
inferior to… value". Statistically this percentile is called
k-1. The border of the 50 percentile (k-50) would correspond
to: "In 505 of the cases the result will be inferior to…"
Table 3 displays the outcomes of the 1000
series with different bet sizes in percents of the capital.
With 10% bet for each trade the minimal
capital after 100 trades was 181,1$. In 1% of all trades our
capital was under $405 (Profit k1). In 50% the trading yielded
$4501 and less (Profit k-50). In 95% of cases the end capital
was below $22411 (Profit k-95), and, corerespondingly, in 5%
of cases the end capital was above $22411.
Let us review drawdowns (DD in the table).
The drawdown is the difference between the maximal capital and
its subsequent minimum before the new maximum is reached. With
10% bets in 50% of the cases the DD was over 48%, in 1% over
78% and the maximal DD was almost 90% of the capital. With
bets over 30% of the capital we ape practically doomed to
ruin. Once again we remind that this game has a positive
expectancy - at win/loss probability 60% to 40% the win size
relates to loss size as 1 to 1.
Steve Cohen says that: "the traders' general
mistake is taking too large positions in relation to their
portfolios. The, when the shares move against them, they are
hurt too much to remain in control, they finally either panic
or freeze in shock"1.
These examples described the importance of
bet size in games with an undetermined outcome. So what is
money management? An Internet search with those keywords
yielded links to services for personal financial control,
advices on handling others' money, how to control risk, on
Turtle Trading, etc. According to Van Tharp, money management
is NOT: · a part of system that dictates how much you
will lose in a given trade · a way to exit a profitable
trade · is not diversification · is not risk
control · is not avoiding risks · is not a part of a
system that maximizes performance · is not a part of the
system that tells where to invest
Money management is a part of a trading
system that tells "how much". How many units of investitions
should be held at a time? How much risk may be taken?
So, money management is controlling the bet
size. Te most radical definition known to us is given by Ryan
Jones3: money management is limited to defining what sum from
your account should be risked on the next trade. Pay attention
that this definition does not list as money management
controlling the size of an already open position, which Van
tharp allows.
Table2.
| %
loss |
10 |
20 |
30 |
40 |
50 |
60 |
70 |
80 |
90 |
| %
profit required to recover |
11,1 |
25,0 |
42,9 |
66,7 |
100 |
150 |
223,3 |
400 |
900 |
Table3.
| Bet
size |
k-50
DD, % |
k-99
DD, % |
Max DD,
% |
Worst
profit case |
k-1
profit |
k-50
profit |
k-95
profit |
| 1.00 |
5.87 |
13.25 |
18.30 |
900 |
956 |
1.215 |
21.426 |
| 5.00 |
26.86 |
52.32 |
68.17 |
484 |
654 |
2.401 |
5.346 |
| 10.00 |
48.43 |
78.36 |
89.49 |
181 |
405 |
4.501 |
22.411 |
| 15.00 |
64.77 |
92.81 |
97.48 |
71 |
237 |
6.586 |
73.936 |
| 40.00 |
98.81 |
100.00 |
100.00 |
0 |
0 |
783 |
687.933 |
Dmitry Tolstonogov
Copyright (c) RT Soft Ltd, TS Research Group Ltd.
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