Algorithmic Trading
Can the next terrorist attack be
based on the human weakness to understand the vulnerabilities of the
algotithmic trading systems?
A personal note
I am a mathematician, so I am supposed to like algorithms.
I love
them. But not always.
I love some algorithms that are
used by traders in algorithmic trading. I
don't believe in algorithms that replace humans in decision making.
That buy and sell without human intervention.
Yes,
these algorithms can be useful, but they can also be very dangerous.
I
do understand that algorithms and automated systems can be very quick
and effective.
For example, I like smart order routing
algorithms, like “Guerrilla”, the algorithm developed by Credit Suisse
that slices big orders into smaller unobtrusive sizes. Great
algorithm, very effective.
I
like “Sniper”, also developed by Credit Suisse, that detects dark
pools of liquidity (hidden sources of liquidity that are not shown on
conventional trading platforms provided by the stock exchanges).
I like “Benchmark” algorithms that achieve a specific benchmark.
The problem is that we take
algorithmic trading far too seriously, we
rely on it, and we run the risk of transforming it from a useful tool
to a weapon of mass destruction (WMD).
Why?
All these algorithms trade according to
well known or predictable rules and can be used against the free
market or the firms that rely on them. This is a disaster waiting to
happen.
Traders do not really
understand information security, deception management, information
systems.
I have never met them in Black Hut conference in Las
Vegas.
They have learned Euclidean geometry, and they
strongly believe that "A Straight Line Is the Shortest Distance
between Two Points". Not always, and definitely not in information
security.
A Straight Line is
the most obvious and most predictable route, and this knowledge can be
used against us.
Anti-Algorithmic Trading
Algorithmic trading is the use of
computer systems, programs and advanced mathematical models for
entering trading orders.
Algorithms, not humans decide
on aspects such as the timing, price and the quantity of orders.
Some algorithms initiate orders based on information received
electronically, understood by the algorithms only.
On the positive side,
they are quick, so
they can exploit opportunities (arbitrage, statistical arbitrage,
trend following).
I like statistical arbitrage, and I remember that I
liked some algorithmic trading systems that really helped, but these
days there are so many sophisticated systems and algorithms competing
to exploit the same opportunities, that we
have to find something more creative.
On the negative side, more and more
trades are driven by automatic programs, and algorithms replace
traders.
At the London Stock
Exchange for example, over 50% of all orders were entered by algo
traders.
American markets have an even higher
proportion of algo trades (estimates range as high as 80% proportion
in some markets).
Electronic platforms were supposed to execute simple trades, and leave
hedge fund managers or traders at the financial firms and brokerages
free to come up with new ideas for making money.
These days
electronic platforms tend to execute all
trades, and leave humans free to find another job. Which one?
Technical staff, as more and more firms have more people working in
their technology area than people on the trading desk.
Computers not only learn what is new from firms such as Reuters, Dow
Jones, Bloomberg and Thomson Financial, but also decide if the news is
good or bad so that automated trading can work directly on the news
stories.
“There is a real interest
in moving the process of interpreting news from the humans to the
machines” said Kiristi Suutani, global business manager of algorithmic
trading at Reuters. Jobs once done by human traders are being switched
to computers.
Every day we read about the speed and the
processing power of computers and networks, and their ability for
“lightning-quick trades”.
When we read success stories about humans, like hedge fund managers,
we also read about their high management and performance fee.
We rarely speak about the cost of the
systems that replace humans (tens of billions).
I do not like
certain algorithms called “sniffers”, that sniff out algorithmic
trading by others and the algorithms being used by them. They can
“game” the system, and may trigger buy orders to generate a better
market price into which to sell.
These algorithms can be very
dangerous.
We move towards Information Operations and
Information Warfare-like environment.Information is no longer a staff
function but an operational one. It is deadly as well as useful.
Executive Summary,
Air Force 2025 report
No, I am
not kidding.
Information Operations
is the integrated employment of the core capabilities of electronic
warfare, computer network operations, psychological operations,
military deception and operations security, in concert with specified
supporting and related capabilities, to influence, disrupt, corrupt or
usurp adversarial human and automated decision making while protecting
our own.
The above definition of Information Operations
should have nothing to do
with trading. But it has.
If you read
the definition carefully, you will see that
trading is very
similar to war, and information is always a weapon.
Hedge funds and financial organizations of both, the buy side and the
sell side, must remember that computers should
help
humans, not make
decisions.
Traders must not forget that they are not IT or
Information Security experts, and that mathematicians are
usually not born for risk management. So many firms rely on systems
they do not understand.
No, these risks are not covered by your risk models. They are 15 standard deviations
from the mean (nowhere).
They are High Impact / Low
Likelihood events, hidden under the "fat tail" of the distribution.
Systems should help humans, not replace
them. I really like
strategies and approaches that can not be programmed into systems.
Creative, non-formulaic, anti-algorithmic.
There is no excuse, it has happened, and it will happen again.
the scale will be dirrerent. We must take steps now.
FINDINGS
REGARDING THE MARKET EVENTS OF MAY 6, 2010 REPORT OF THE STAFFS OF
THE CFTC AND SEC TO THE JOINT ADVISORY COMMITTEE ON EMERGING
REGULATORY ISSUES

This is a
report of the findings by the staffs of the
U.S. Commodity Futures Trading Commission and the U.S. Securities and
Exchange Commission.
The Commissions have expressed no
view regarding the analysis, findings or conclusions contained herein.
This report presents findings of the staffs of the Commodity
Futures Trading Commission (“CFTC”) and the Securities and Exchange
Commission (“SEC” and collectively, the “Commissions”) to the Joint
CFTC-SEC Advisory Committee on Emerging Regulatory Issues (the
“Committee”) regarding the market events of May 6, 2010.
This
report builds upon the initial analyses of May 6 performed by the
staffs of the Commissions and released in the May 18, 2010, public
report entitled Preliminary Findings Regarding the Market Events of
May 6, 2010 – Report of the Staffs of the CFTC and SEC to the Joint
Advisory Committee on Emerging Regulatory Issues (the “Preliminary
Report”).
Readers are encouraged to review the Preliminary
Report for important background discussions and analyses that are
referenced but not repeated herein.
EXECUTIVE SUMMARY
On May 6, 2010,
the prices of many U.S.-based equity
products experienced an extraordinarily rapid decline and recovery.
That afternoon, major equity indices in both the
futures and securities markets, each already down over 4% from their
prior-day close, suddenly plummeted a
further 5-6% in a matter of minutes before rebounding almost as
quickly.
Many of the almost 8,000 individual equity
securities and exchange traded funds (“ETFs”) traded that day suffered
similar price declines and reversals within a short period of time,
falling 5%, 10% or even 15% before
recovering most, if not all, of their losses.
However,
some equities experienced even more severe price moves, both up and
down.
Over 20,000 trades across
more than 300 securities were executed at prices more than 60% away
from their values just moments before.
Moreover, many
of these trades were executed at prices of a penny or less, or as high
as $100,000, before prices of those securities returned to their
“pre-crash” levels.
By the end of
the day, major futures and equities indices “recovered” to close at
losses of about 3% from the prior day.
WHAT HAPPENED?
May 6 started
as an unusually turbulent day for the markets.
As discussed in
more detail in the Preliminary Report,
trading in the U.S opened to unsettling political and economic news
from overseas concerning the European debt crisis.
As a
result, premiums rose for buying protection against default by the
Greek government on their sovereign debt.
At about 1 p.m.,
the Euro began a sharp decline against both
the U.S Dollar and Japanese Yen.
Around 1:00 p.m.,
broadly negative market sentiment was already affecting an increase in
the price volatility of some individual securities.
At that
time, the number of volatility pauses, also known as
Liquidity Replenishment Points (“LRPs”),
triggered on the New York Stock Exchange (“NYSE”) in individual
equities listed and traded on that exchange began to substantially
increase above average levels.
By 2:30 p.m.,
the S&P 500 volatility index (“VIX”) was up
22.5 percent from the opening level, yields of ten-year
Treasuries fell as investors engaged in a “flight to quality,” and
selling pressure had pushed the Dow Jones Industrial Average (“DJIA”)
down about 2.5%.
Furthermore, buy-side liquidity3 in the E-Mini
S&P 500 futures contracts (the “E-Mini”), as well as the S&P 500 SPDR
exchange traded fund (“SPY”), the two most active stock index
instruments traded in electronic futures and equity markets,
had fallen from the early-morning level of
nearly $6 billion dollars to $2.65 billion (representing a 55%
decline) for the E-Mini and from the early-morning level of
about $275 million to $220 million (a 20% decline) for SPY.
Some individual stocks also suffered from a
decline their liquidity.
At 2:32 p.m., against this
backdrop of unusually high volatility and thinning liquidity, a large
fundamental5 trader (a mutual fund complex) initiated a sell program
to sell a total of 75,000 E-Mini contracts (valued at approximately
$4.1 billion) as a hedge to an existing equity position.
Generally, a customer has a number of alternatives as to how to
execute a large trade.
First, a
customer may choose to engage an intermediary, who would, in
turn, execute a block trade or manage the position.
Second, a customer may choose to manually
enter orders into the market.
Third, a customer can execute a trade via an automated execution
algorithm, which can meet the customer’s needs by taking price,
time or volume into consideration.
Effectively, a customer
must make a choice as to how much human judgment is involved while
executing a trade.
This large
fundamental trader chose to execute this sell program via an automated
execution algorithm (“Sell Algorithm”) that was programmed to feed
orders into the June 2010 E-Mini market to target an execution rate
set to 9% of the trading volume calculated over the previous minute,
but without regard to price or time.
The execution of
this sell program resulted in the largest net change in daily position
of any trader in the E-Mini since the beginning of the year (from
January 1, 2010 through May 6, 2010).
Only two single-day sell
programs of equal or larger size – one of which was by the same large
fundamental trader – were executed in the E-Mini in the 12 months
prior to May 6.
When executing the previous sell program,
this large fundamental trader utilized a
combination of manual trading entered over the course of a day and
several automated execution algorithms which took into account price,
time, and volume.
On that occasion it took more than 5
hours for this large trader to execute the first 75,000 contracts of a
large sell program.
However, on May 6, when markets were
already under stress, the Sell Algorithm
chosen by the large trader to only target trading volume, and neither
price nor time, executed the sell program extremely rapidly in just 20
minutes.
This sell pressure was initially absorbed by:
• high frequency traders (“HFTs”) and other intermediaries8 in the
futures market;
• fundamental buyers in the futures market; and
• cross-market arbitrageurs9 who transferred this sell pressure to
the equities markets
by opportunistically buying E-Mini
contracts and simultaneously selling products like SPY, or selling
individual equities in the S&P 500 Index.
HFTs and
intermediaries were the likely buyers of the initial batch of orders
submitted by the Sell Algorithm, and, as a result, these buyers built
up temporary long positions. Specifically, HFTs accumulated a net long
position of about 3,300 contracts.
However, between 2:41 p.m. and 2:44 p.m., HFTs aggressively sold about
2,000 E-Mini contracts in order to reduce their temporary long
positions.
At the same time, HFTs traded nearly 140,000 E-Mini
contracts or over 33% of the total trading volume.
This
is consistent with the HFTs’ typical practice of trading a very large
number of contracts, but not accumulating an aggregate inventory
beyond three to four thousand contracts in either direction.
The Sell Algorithm used by the large trader
responded to the increased volume by increasing the rate at which it
was feeding the orders into the market, even though orders that it
already sent to the market were arguably not yet fully absorbed by
fundamental buyers or cross-market arbitrageurs.
In
fact, especially in times of significant volatility, high trading
volume is not necessarily a reliable indicator of market liquidity.
What happened next is best described in terms of
two liquidity crises – one at the broad
index level in the E-Mini, the other with respect to individual
stocks.
LIQUIDITY CRISIS IN
THE E-MINI
The combined selling pressure from the Sell
Algorithm, HFTs and other traders drove the price of the E-Mini down
approximately 3% in just four minutes from the beginning of 2:41 p.m.
through the end of 2:44 p.m.
During this same time
cross-market arbitrageurs who did buy the E-Mini, simultaneously sold
equivalent amounts in the equities markets, driving the price of SPY
also down approximately 3%.
Still lacking sufficient demand
from fundamental buyers or cross-market arbitrageurs, HFTs began to
quickly buy and then resell contracts to each other – generating a
“hot-potato” volume effect as the same positions were rapidly passed
back and forth.
Between 2:45:13 and
2:45:27, HFTs traded over 27,000 contracts, which accounted for about
49 percent of the total trading volume, while buying only about 200
additional contracts net.
At this time, buy-side market
depth in the E-Mini fell to about $58 million, less than 1% of its
depth from that morning’s level.
As
liquidity vanished, the price of the E-Mini dropped by an additional
1.7% in just these 15 seconds, to reach its intraday low of 1056.
This sudden decline in both price and liquidity may be
symptomatic of the notion that prices were moving so fast, fundamental
buyers and cross-market arbitrageurs were either unable or unwilling
to supply enough buy-side liquidity.
In the four-and-one-half minutes from 2:41
p.m. through 2:45:27 p.m., prices of the E-Mini had fallen by more
than 5% and prices of SPY suffered a decline of over 6%.
According to interviews with cross-market trading firms, at this
time they were purchasing the E-Mini and selling either SPY, baskets
of individual securities, or other index products.
By 2:45:28
there were less than 1,050 contracts of buy-side resting orders in the
E-Mini, representing less than 1% of buy-side market depth observed at
the beginning of the day.
At the same time, buy-side resting
orders in SPY fell to about 600,000 shares (equivalent to 1,200 E-Mini
contracts) representing approximately 25% of its depth at the
beginning of the day.
Between 2:32 p.m. and 2:45 p.m., as
prices of the E-Mini rapidly declined, the
Sell Algorithm sold about 35,000 E-Mini contracts (valued at
approximately $1.9 billion) of the 75,000 intended.
During the same time, all fundamental
sellers combined sold more than 80,000 contracts net, while all
fundamental buyers bought only about 50,000 contracts net, for a net
fundamental imbalance of 30,000 contracts.
This level
of net selling by fundamental sellers is about 15 times larger
compared to the same 13-minute interval during the previous three
days, while this level of net buying by the fundamental buyers is
about 10 times larger compared to the same time period during the
previous three days.
At 2:45:28 p.m.,
trading on the E-Mini was paused for five
seconds when the Chicago Mercantile Exchange (“CME”) Stop Logic
Functionality was triggered in order to prevent a cascade of further
price declines.
In that short period of time, sell-side
pressure in the E-Mini was partly alleviated and buy-side interest
increased.
When trading resumed at 2:45:33 p.m., prices
stabilized and shortly thereafter, the E-Mini began to recover,
followed by the SPY.
LIQUIDITY
CRISIS WITH RESPECT TO INDIVIDUAL STOCKS
The
second liquidity crisis occurred in
the equities markets at about 2:45 p.m.
Based on interviews
with a variety of large market participants,
automated trading systems used by many
liquidity providers temporarily paused in reaction to the sudden price
declines observed during the first liquidity crisis.
These built-in pauses are designed to prevent automated systems from
trading when prices move beyond pre-defined thresholds in order to
allow traders and risk managers to fully assess market conditions
before trading is resumed.
After their trading systems were
automatically paused, individual market participants had to assess the
risks associated with continuing their trading.
Participants
reported that these assessments included the following factors:
whether observed severe price moves could be an artifact of erroneous
data; the impact of such moves on risk and position limits; impacts on
intraday profit and loss (“P&L”); the potential for trades to be
broken, leaving their firms inadvertently long or short on one side of
the market; and the ability of their systems to handle the very high
volume of trades and orders they were processing that day.
In
addition, a number of participants reported that
because prices simultaneously fell across
many types of securities, they feared the occurrence of a cataclysmic
event of which they were not yet aware, and that their strategies were
not designed to handle.
Based on their respective
individual risk assessments, some market makers and other liquidity
providers widened their quote spreads, others reduced offered
liquidity, and a significant number withdrew completely from the
markets.
Some fell back to manual trading but
had to limit their focus to only a subset
of securities as they were not able to keep up with the nearly
ten-fold increase in volume that occurred as prices in many securities
rapidly declined.
HFTs in the equity markets, who
normally both provide and take liquidity as part of their strategies,
traded proportionally more as volume increased, and overall were net
sellers in the rapidly declining broad market along with most other
participants.
Some of these firms continued to trade as the
broad indices began to recover and individual securities started to
experience severe price dislocations, whereas others reduced or halted
trading completely.
Many over-the-counter (“OTC”) market makers
who would otherwise internally execute as principal a significant
fraction of the buy and sell orders they receive from retail customers
(i.e., “internalizers”) began routing most, if not all, of these
orders directly to the public exchanges where they competed with other
orders for immediately available, but dwindling, liquidity.
Even though after 2:45 p.m. prices in the E-Mini and SPY were
recovering from their severe declines, sell orders placed for some
individual securities and ETFs (including many retail stop-loss
orders, triggered by declines in prices of those securities) found
reduced buying interest, which led to
further price declines in those securities.
Between 2:40 p.m. and 3:00 p.m.,
approximately 2 billion shares traded with a total volume exceeding
$56 billion. Over 98% of all shares were executed at prices within 10%
of their 2:40 p.m. value.
However, as liquidity
completely evaporated in a number of individual securities and ETFs,11
participants instructed to sell (or buy) at the market found no
immediately available buy interest (or sell interest) resulting in
trades being executed at irrational prices as low as one penny or as
high as $100,000.
These trades occurred as a result of
so-called stub quotes, which are quotes generated by market makers (or
the exchanges on their behalf) at levels far away from the current
market in order to fulfill continuous two-sided quoting obligations
even when a market maker has withdrawn from active trading.
The
severe dislocations observed in many securities were fleeting.
As market participants had time to react and verify the integrity
of their data and systems, buy-side and
sell-side interest returned and an orderly price discovery process
began to function.
By approximately 3:00 p.m., most
securities had reverted back to trading at prices reflecting true
consensus values.
Nevertheless,
during the 20 minute period between 2:40 p.m. and 3:00 p.m., over
20,000 trades (many based on retail-customer orders) across more than
300 separate securities, including many ETFs,12 were executed at
prices 60% or more away from their 2:40 p.m. prices.
After the market closed, the exchanges and FINRA met and jointly
agreed to cancel (or break) all such trades under their respective
“clearly erroneous” trade rules.
LESSONS LEARNED
The events summarized above and
discussed in greater detail below highlight a number of key lessons to
be learned from the extreme price movements observed on May 6.
One key lesson is that under stressed
market conditions, the automated execution of a large sell order can
trigger extreme price movements, especially if the automated execution
algorithm does not take prices into account.
Moreover,
the interaction between automated execution
programs and algorithmic trading strategies can quickly erode
liquidity and result in disorderly markets.
As the
events of May 6 demonstrate, especially in times of significant
volatility, high trading volume is not necessarily a reliable
indicator of market liquidity.
May 6 was also an important
reminder of the inter-connectedness of our derivatives and securities
markets, particularly with respect to index products.
The
nature of the cross-market trading activity described above was
confirmed by extensive interviews with market participants (discussed
more fully herein), many of whom are active in both the futures and
cash markets in the ordinary course, particularly with respect to
“price discovery” products such as the E-Mini and SPY.
Indeed,
the Committee was formed prior to May 6 in recognition of the
continuing convergence between the securities and derivatives markets,
and the need for a harmonized regulatory approach that takes into
account cross-market issues.
Among other potential areas to
address in this regard, the staffs of the CFTC and SEC are working
together with the markets to consider recalibrating the existing
market-wide circuit breakers – none of which were triggered on May 6 –
that apply across all equity trading venues and the futures markets.
Another key lesson from May 6 is that many market participants
employ their own versions of a trading pause – either generally or in
particular products – based on different combinations of market
signals.
While the withdrawal of a single participant may not
significantly impact the entire market, a
liquidity crisis can develop if many market participants withdraw at
the same time.
This, in turn, can lead to the breakdown
of a fair and orderly price-discovery process, and in the extreme case
trades can be executed at stub-quotes used by market makers to fulfill
their continuous two-sided quoting obligations.
As demonstrated by the CME’s Stop Logic
Functionality that triggered a halt in E-Mini trading, pausing a
market can be an effective way of providing time for market
participants to reassess their strategies, for algorithms to reset
their parameters, and for an orderly market to be re-established.
In response to this phenomenon, and to curtail the possibility
that a similar liquidity crisis can result in circumstances of such
extreme price volatility, the SEC staff worked with the exchanges and
FINRA to promptly implement a circuit breaker pilot program for
trading in individual securities.
The circuit breakers pause
trading across the U.S. markets in a security for five minutes if that
security has experienced a 10% price change over the preceding five
minutes.
On June 10, the SEC
approved the application of the circuit breakers to securities
included in the S&P 500 Index, and on September 10, the SEC approved
an expansion of the program to securities included in the Russell 1000
Index and certain ETFs.
The circuit breaker program is in
effect on a pilot basis through December 10, 2010.
A
further observation from May 6 is that
market participants’ uncertainty about when trades will be broken can
affect their trading strategies and willingness to provide liquidity.
In fact, in our interviews many participants expressed concern that,
on May 6, the exchanges and FINRA only broke trades that were more
than 60% away from the applicable reference price, and did so using a
process that was not transparent.
To provide market
participants more certainty as to which trades will be broken and
allow them to better manage their risks, the SEC staff worked with the
exchanges and FINRA to clarify the process for breaking erroneous
trades using more objective standards.
On September 10, the SEC
approved the new trade break procedures, which like the circuit
breaker program, is in effect on a pilot basis through December 10,
2010. Going forward, SEC staff will evaluate the operation of the
circuit breaker program and the new procedures for breaking erroneous
trades during the pilot period.
As part of its review,
SEC staff intends to assess whether the
current circuit breaker approach could be improved by adopting or
incorporating other mechanisms, such as a limit up/limit down
procedure that would directly prevent trades outside of specified
parameters, while allowing trading to continue within those
parameters.
Such a procedure could prevent many
anomalous trades from ever occurring, as well as limit the disruptive
effect of those that do occur, and may work well in tandem with a
trading pause mechanism that would accommodate more fundamental price
moves. Of final note, the events of May 6 clearly demonstrate the
importance of data in today’s world of fully-automated trading
strategies and systems.
This is further complicated by the
many sources of data that must be aggregated in order to form a
complete picture of the markets upon which decisions to trade can be
based.
Varied data conventions,
differing methods of communication, the sheer volume of quotes,
orders, and trades produced each second, and even inherent time lags
based on the laws of physics add yet more complexity.
Whether trading decisions are based on
human judgment or a computer algorithm, and whether trades occur once
a minute or thousands of times each second, fair and orderly markets
require that the standard for robust, accessible, and timely market
data be set quite high.
Although we do not believe
significant market data delays were the primary factor in causing the
events of May 6, our analyses of that day reveal the extent to which
the actions of market participants can be influenced by uncertainty
about, or delays in, market data.
Accordingly,
another area of focus going forward should
be on the integrity and reliability of market centers’ data processes,
especially those that involve the publication of trades and quotes to
the consolidated market data feeds.
In addition, we
will be working with the market centers in exploring their members’
trading practices to identify any unintentional or potentially abusive
or manipulative conduct that may cause system delays that inhibit the
ability of market participants to engage in a fair and orderly process
of price discovery.
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