Excerpts from
Data Mining Solutions: Methods and Tools For Solving Real World Problems
by Christopher Westphal & Teresa
Blaxton, John Wiley and Sons Inc.
Case Studies:
1.
Managing Investments in an Unstable Asian Banking Market
2.
Managing Declines in the Technical Sector
3.
Discovery of Insider Trading Patterns
Wall Street and
other financial markets are increasingly turning to the use of visual
data mining techniques to deal with large quantities of data. This
chapter introduced a set of data mining applications in which Metaphor
Mixer (MM) was used to discover and analyze some very complicated
patterns of data within the Asian financial markets. One of the MM
applications was used to identify a significant downward trend in
the Japanese banking system by taking advantage of financial indicators
that were modeled at the time. By visually presenting all of the variables
within the market, the institution was able to discover this trend
early and respond by moving some of their risky investments into more
secure and convertible instruments. Thus the fund was well prepared
when the collapse occurred. The other application was helpful in revealing
a pattern of insider trading by a Japanese firm. Managers of the fund
were able to take advantage of the situation legally by adjusting
their own acquisitions so as to maximize profits as stock prices were
instrumental in this situation because it not only helped the fund
managers to discover the pattern but was also used to justify buying
and selling behaviors to the SEC when they investigated the matter
several years later.
Managing
Investments in an Unstable Asian Banking Market
The data mining
activity described here occurred between January and April of 1992
and involved investments made by the institution within the Asian
markets for a particular actively managed index fund. For those who
may remember, banks in Japan and other Asian countries became unstable
and inherently volatile during that period. The prices associated
with many of their stocks tumbled, producing record losses across
the board. Even though the markets for all industries took a big drop,
the banking industry was hardest hit. This narrative describes what
happened with the Japanese banks, how this investment firm identified
the weakness, and what they did to turn it into an opportunity to
make record profits.
METAPHOR MIXER (MM) was chosen for this application because
its information terrain paradigm was an ideal representation for helping
to manage the analysis of large quantities of complex financial data.
The border elements (e.g., grid axes) defined within the application
were configured to represent different target analysis groups. Along
one dimension were the industry segments such as electronics, financial,
construction, manufacturing, utilities, automotive, paper, and so
on. On the other dimension were Asian financial markets including
Japan, Thailand, Singapore, Malaysia, Indonesia, and Hong Kong. (Figure
1 shows the border elements defined for this application.) Multiple
levels of abstraction could also be presented within the border elements
by adjusting the breakdowns represented (e.g., various types of consumer
electrical equipment, certain categories of automotive manufacturing,
or even the orientation of the different financial investments used
by the banks). Within each cell of the matrix produced by the border
elements selected by the portfolio manager were objects that represented
the individual stocks being traded within their respective markets.
The objects, also referred to as chips, could be manipulated on several
dimensions including color, shape, and presentation style (e.g., blinking
and spinning) to convey further information about performance, behavior
and future projections.
Figure 1

The information
terrain within this application depicted the stock data using a variety
of display dimensions. The color of a particular stock in the display
conveyed information about how well it was performing with respect
to its market index. A red chip indicated that the stock was down
in value from a previous posting (e.g., usually tied to a daily value)
whereas a blue chip showed a positive value. The color gray signified
no substantial change in price. The baseline of the MM display was
set to the index of the market being analyzed. The height of the chips
within the terrain showed how far above or below the index the particular
stock was performing. A spinning chip indicated that a stock had attractive
characteristics such as a low price-to-earnings ratio with high earnings
potential (referred to as a low p/e growth rate). Blinking was tied
to certain arbitrage possibilities as determined by the stock's options
or warrants. If that same data element had an arrow vector pointing
out, it would also indicate the stock had some sort of low technical
indicator, such as a moving average. This provided a third decision
element that reinforced the portfolio manager's judgment to buy a
stock or look more closely at it because three very important outlier
statistics had been flagged on that security element. (Figure 2 presents
an example of a MM display showing the different display characteristics
for this type of information.)
Figure 2

Within this MM application, the portfolio manager was able to incorporate
as much knowledge as possible from the available information and make
more informed and timely decisions. He was able to isolate anomalies
and potential opportunities using a topsight display that allowed
him to drill-down and focus on specific market indicators. This guided
further investigation of various options and investment strategies.
The portfolio manager also used the MM system to key in on estimates
made by various brokers who were analyzing the companies in the index.
At the same time, MM was fusing background information, real time
data, and consensus estimates from brokers regarding projected earnings.
Live news feeds could be scanned to look for keywords indicating earnings
surprises or shortfalls. As these were identified off the news service,
the MM agent would pop up and drag the portfolio manager's viewpoint
to that element and display the headline to the news wire story. This
arrangement resulted in a decision space that integrated historical,
current, and future estimates data into one model that supported situational
awareness of the market at any given time. At this point, the institution
had an operational visualization environment that allowed its portfolio
managers to do screen searches and sorts on all of these integrated
variables.
Because of their use of this MM application, the institution was one
of the first firms participating in the Asian markets to identify
the initial slide in 1992, identifying the price change collapse as
well as other fundamental and technical analysis elements. One trend
that was spotted early on involved equities and convertible bonds
issued by the Bank of Tokyo. Depending on price, investors may want
to trade convertible bonds like equities. A convertible bond with
an "exercise price" far higher than the market price of
a stock generally trades at its bond value, although the yield is
usually a little higher due to its lower credit status. However, when
the bond's share price is sufficiently high, traders want to use the
convertible more like an equity. If the exercise price is much lower
than the market price of the common shares, the holder of the convertible
bonds can convert into the stock attractively. Issuers sell convertible
bonds to provide a higher current yield to investors and equity capital
upon conversion. Investors buy convertible bonds to gain a higher
current yield and less downside, since the convertible should trade
to its bond value in the case of a steep drop in the common share
price.
What happened in this case was that the investment firm saw that the
equities issued by the Bank of Tokyo were decaying at the same time
that convertible bond arbitrage opportunities were being made available.
This was conveyed in the MM application by coding colors, heights,
spins, and blinks to fuse the convertible bond information with that
of the underlying bank's stocks. Analysts were able to see that market
volatility was increasing by changes in the spinning and the blinking
in the displays. However, there were also indicators showing that
a convertible bond issue that was available that could be swapped
out for the stock. These behaviors were being displayed in real time
in the application and when the big crash came and everything went
red in MM (e.g., all the chips dropped below the baseline- see Figure
3), the firm had already safely ensconced most of their capital in
convertible bonds. This was an important move because of the way the
firm evaluated the performance of its investments. Specifically, the
Japanese bank markets formed a major portion of the index against
which performance was assessed. Thus, the firm wanted to participate
in the banking industry because it comprised such a large portion
of the index, and buying into the convertible bonds allowed them to
be in the banking market without realizing losses when the stock prices
dropped. In addition, the investment in the Bank of Tokyo's convertible
bonds and others like it allowed the fund to maintain its currency
in yen mandated for the portfolio's diversification requirements.
By being alert to the growing sector instabilities and anticipating
a sudden volatility spike, the portfolio manager took advantage of
the situation. Below we will explain in detail how he was to surf
the downside curvature of a convertible bond.
Figure 3

When the market crashed, the convertible bonds did not go down. Instead,
they actually went up in price. This occurred because in the panic
sell-off of the market, the Japanese government was forced to lower
its interest rates. As with all markets, bonds are inversely proportional
to the interest rates. So when the rates are lowered, bond prices
increase. On average, the Japanese stocks dropped over 15 percent
in value while the convertible bonds increased 10 percent in the same
time interval. This meant that the pension fund outperformed the market
by 2500 basis points. (To say that this was a good outcome is a gross
understatement.) Thus, it was an intelligent move in terms of identifying
a weakness and finding the attractive alternative possibilities. This
investment tactic would likely not have been pursued without the use
of MM. That is, the firm used MM to fuse the real-time data with arbitrage
information and the historical earnings estimated into one display
state in addition to sorting by industry groups and countries. This
allowed them to see early on that the weakest part of the industry
was the Japanese banking sector. Thus on April 8, 1992, when the market
took its hit, the portfolio managers were sitting pretty because they
had already been able to predict the collapse and redirect some of
their Asian banking investments into convertible bonds. This resulted
in an initial gain of approximately $10 million dollars. Had they
not taken this action they might have lost between $30 and $40 million,
so the "real" net gain approached $40-$50 million dollars.
The institution has maintained their investment in convertible bonds,
and over the past several years the Japanese banks have still continued
to decay. However the fact that much of the investments were swapped
into convertible bonds early meant that they never lost ground. The
investments were always in the index with the stock, and they were
earning a rate of return from convertible bond interest instead of
getting nothing from equities.
Managing
Declines in the Technical Sector
A crisis similar
to the Japanese banking crash occurred in he summer of 1996 in the
technology sector. The crisis was identified in MM using similar information
fusion technologies as those employed in the Asian market application.
In this case the recovery of the market was also tracked. Red icons
in the MM landscape grid depicted drops in stock prices below the
baseline. Quaking in the icons depicted further day-to-day drops and
spinning icons showed low price-to-book ratios. Blinking was keyed
to high returns on equity. Figures 4 & 5 show sample MM displays
depicting the U.S. technology market information.
Figure 4

During the period initially following the crash, all of the stocks
were below baseline and were, not surprisingly, oversold. The challenge
was to determine whether anything might be salvaged from the situation.
Although the stocks in question were shown to be below baseline in
the MM application, analysts were able to determine that some of these
stocks might be good investments because some of their fundamental
indicators (shown as arrows on the icons) started to show upward
trends. That is, the analysts were able to determine that even though
the technology sector had bottomed out, certain stocks showed behaviors
that made them less risky for investment at that time. The type of
data visualization provided by MM helped the financial managers to
determine which of the hundreds of stocks merited further attention,
even within a market that had recently crashed. Note that there was
no magical black box that told analysts when to but, but the use of
visualization allowed knowledgeable analysts to make the most out
of information at hand.
Figure 5

The information maintained in the MM terrain during the technology
crash episode can be replayed using the MM's VCR feature. Analysts
in the company can replay a movie that includes data collected over
3-4 months before, during and after the crash. The VCR replay shows
when stock prices bottomed out, identifies which interests and industry
groups were most severely affected, and shows the return of certain
key stocks within the overall population.
Discovery
of Insider Trading Patterns
Using what would
eventually become the MM inference engine, the investment firm developed
an application that displayed the activity profiles of a set of stocks
that were members of an Asian index. In this application the analysts
were particularly interested in monitoring patterns of trading volumes
of a set of Japanese stocks. One of the most salient stocks identified
by the institution was a large Japanese-based corporation that was
cyclically manipulated in an insider trading scam by a group of Japanese
investors. Regular patterns of volume spikes were discovered in the
trading data for this stock. The patterns began with an initial day
of elevated trading that would move a set of stocks up 5-10 percent
in value (See Figure 6). The elevated trading would last up to five
days. This initial period was then followed three to six months later
by a precipitous drop in prices. The pattern occurred with remarkable
regularity and, as it turned out, signaled the operation of an insider
trading scam.
Figure 6

Since any of the stocks being manipulated were typically poor performers,
they were likely to be underweighted within the portfolios maintained
by investment managers. The frenzy of buying by the insider traders
significantly inflated the price of the stock, thereby casing a big
delta in the index ratios expected for the portfolio. Large portfolio
managers then purchased the stock, the insider traders sold at the
higher price, and the portfolio managers took a loss as the price
eventually fell back to its true price range.
Once the pattern of insider trading was discovered using MM, the portfolio
manager at the investment firm was able to avoid losses on this stock.
The manager purchased only enough stock to achieve market weight,
so that the investment could track with the index. However, the manger
did not over purchase the stock, thus setting himself up for a loss.
That is, since the manager knew that the price was going to fall,
he arranged his investments so as to shield against any index fluctuations
while selling out of the stock as it hit its highest levels. Thus,
by discovering this pattern of insider trading, our investment company
was able to beat the insider traders at their own game using legal
means, thus saving their clients millions of dollars. As it turned
out, the insider traders became aware of the actions of the investment
firm, and believed that a pension fund manager must have been receiving
leaks of inside information from someone involved in the scam. Nevertheless,
they were hardly in a position to do anything about it since any complaint
would have drawn attention to their own illegal activities. (Little
did they know that it was sophisticated data mining analysis, rather
than information leaks, that had given them away.
Excerpt from Data Mining
Solutions: Methods and Tools For Solving Real World Problems by Christopher Westphal & Teresa
Blaxton. Used by arrangement with John Wiley and Sons Inc. All rights reserved.