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	<title>Comments on: How Software Models Doomed the Markets</title>
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	<link>http://www.ritholtz.com/blog/2008/12/how-software-models-doomed-the-markets/</link>
	<description>Macro Perspective on the Capital Markets, Economy, Geopolitics, Technology, and Digital Media</description>
	<lastBuildDate>Tue, 14 Feb 2012 22:30:38 +0000</lastBuildDate>
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		<title>By: gorobei</title>
		<link>http://www.ritholtz.com/blog/2008/12/how-software-models-doomed-the-markets/comment-page-1/#comment-133400</link>
		<dc:creator>gorobei</dc:creator>
		<pubDate>Mon, 15 Dec 2008 07:07:31 +0000</pubDate>
		<guid isPermaLink="false">http://www.ritholtz.com/blog/?p=10482#comment-133400</guid>
		<description>Yohei, you have good taste in movies.</description>
		<content:encoded><![CDATA[<p>Yohei, you have good taste in movies.</p>
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		<title>By: Yohei</title>
		<link>http://www.ritholtz.com/blog/2008/12/how-software-models-doomed-the-markets/comment-page-1/#comment-133399</link>
		<dc:creator>Yohei</dc:creator>
		<pubDate>Mon, 15 Dec 2008 07:03:07 +0000</pubDate>
		<guid isPermaLink="false">http://www.ritholtz.com/blog/?p=10482#comment-133399</guid>
		<description>gorobei,

I am looking forward to your future post as well.  

Recognized your nom de plume immediately and so picked mine, and rather appropriately, I think!</description>
		<content:encoded><![CDATA[<p>gorobei,</p>
<p>I am looking forward to your future post as well.  </p>
<p>Recognized your nom de plume immediately and so picked mine, and rather appropriately, I think!</p>
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		<title>By: Mark E Hoffer</title>
		<link>http://www.ritholtz.com/blog/2008/12/how-software-models-doomed-the-markets/comment-page-1/#comment-133395</link>
		<dc:creator>Mark E Hoffer</dc:creator>
		<pubDate>Mon, 15 Dec 2008 06:03:49 +0000</pubDate>
		<guid isPermaLink="false">http://www.ritholtz.com/blog/?p=10482#comment-133395</guid>
		<description>gorobei,

thanks for the additional...upon re-reading my post @December 14th, 2008 at 9:10 pm, I see I was less than clear.

I was meaning that 2. and 4. Should be explained, b/c 1. and 3. were less difficult, more accessible..

tho, seeing this: December 14th, 2008 at 11:55 pm, thanks again~</description>
		<content:encoded><![CDATA[<p>gorobei,</p>
<p>thanks for the additional&#8230;upon re-reading my post @December 14th, 2008 at 9:10 pm, I see I was less than clear.</p>
<p>I was meaning that 2. and 4. Should be explained, b/c 1. and 3. were less difficult, more accessible..</p>
<p>tho, seeing this: December 14th, 2008 at 11:55 pm, thanks again~</p>
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	<item>
		<title>By: gorobei</title>
		<link>http://www.ritholtz.com/blog/2008/12/how-software-models-doomed-the-markets/comment-page-1/#comment-133390</link>
		<dc:creator>gorobei</dc:creator>
		<pubDate>Mon, 15 Dec 2008 04:55:37 +0000</pubDate>
		<guid isPermaLink="false">http://www.ritholtz.com/blog/?p=10482#comment-133390</guid>
		<description>constantnormal,  hang on a little while, the explanation is proving to be a bit longer than I anticipated :(</description>
		<content:encoded><![CDATA[<p>constantnormal,  hang on a little while, the explanation is proving to be a bit longer than I anticipated :(</p>
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		<title>By: constantnormal</title>
		<link>http://www.ritholtz.com/blog/2008/12/how-software-models-doomed-the-markets/comment-page-1/#comment-133379</link>
		<dc:creator>constantnormal</dc:creator>
		<pubDate>Mon, 15 Dec 2008 04:11:25 +0000</pubDate>
		<guid isPermaLink="false">http://www.ritholtz.com/blog/?p=10482#comment-133379</guid>
		<description>@gorobei -- how about a skeleton outline (at least) of #2.  History (esp. mathematical) and personalities are always fun for me.  A long time ago, in another life, I had a fair understanding of the work of Gauss and Cauchy.  But that was a long time ago.</description>
		<content:encoded><![CDATA[<p>@gorobei &#8212; how about a skeleton outline (at least) of #2.  History (esp. mathematical) and personalities are always fun for me.  A long time ago, in another life, I had a fair understanding of the work of Gauss and Cauchy.  But that was a long time ago.</p>
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		<title>By: constantnormal</title>
		<link>http://www.ritholtz.com/blog/2008/12/how-software-models-doomed-the-markets/comment-page-1/#comment-133374</link>
		<dc:creator>constantnormal</dc:creator>
		<pubDate>Mon, 15 Dec 2008 03:37:03 +0000</pubDate>
		<guid isPermaLink="false">http://www.ritholtz.com/blog/?p=10482#comment-133374</guid>
		<description>Ahem.  Allow me to point out the elephant in the discussion forum.

Is not TMA merely another way to model the future based on the dependent variables of price and volume?

It may not be as precise as these more &quot;sophisticated&quot; automated trading algorithms, but the premise is the same, and it suffers from the same fallibility.

Looking for a method of predicting movements in a hugely complex system of human interactions is fine, but don&#039;t bet your future on it.  You can back-test algorithms to the Big Bang, but there&#039;s no guarantee that the future will conform.  I suspect that one could wrap this into the context of The Halting Problem and logically show it to be impossible.

Instead, design hedging strategies that always work -- which is no small feat in itself.</description>
		<content:encoded><![CDATA[<p>Ahem.  Allow me to point out the elephant in the discussion forum.</p>
<p>Is not TMA merely another way to model the future based on the dependent variables of price and volume?</p>
<p>It may not be as precise as these more &#8220;sophisticated&#8221; automated trading algorithms, but the premise is the same, and it suffers from the same fallibility.</p>
<p>Looking for a method of predicting movements in a hugely complex system of human interactions is fine, but don&#8217;t bet your future on it.  You can back-test algorithms to the Big Bang, but there&#8217;s no guarantee that the future will conform.  I suspect that one could wrap this into the context of The Halting Problem and logically show it to be impossible.</p>
<p>Instead, design hedging strategies that always work &#8212; which is no small feat in itself.</p>
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	<item>
		<title>By: gorobei</title>
		<link>http://www.ritholtz.com/blog/2008/12/how-software-models-doomed-the-markets/comment-page-1/#comment-133351</link>
		<dc:creator>gorobei</dc:creator>
		<pubDate>Mon, 15 Dec 2008 02:10:25 +0000</pubDate>
		<guid isPermaLink="false">http://www.ritholtz.com/blog/?p=10482#comment-133351</guid>
		<description>Mark,

as you note, 1 and 3 are the easy ones.

#1 basically killed Wall St.  Once you switch from a partnertship to a LLC, the game is over:  yes, increased access to capital markets lets you do bigger deals, but 1) the compensation time-horizon shrinks from 30+ years to 5 years or so, and 2) the people at risk become a diffuse pool.

Without a pool of 1000 or so of partners and limited partners (the retired MDs,) it&#039;s all too obvious what happens next:  people lever the one big asset (firm reputation,)  and make great returns for a decade.  Which brings us to point#3:

Few people were trying to be evil, they just optimized given the structure in place.  GS, for example, lined up a $40 billion short-term credit facility:  seemed prudent and conservative.  Then they paid their top producers really well:  again, very reasonable, theys guys made the money for the firm.

But the firm completely missed where the real risk was:  you can&#039;t lever reputation!  Traditionally, most partnerships fall into one of  four categories:  doctors, laywers, accountants, and investment banks:  all charge high fees because the service is opaque and thus putting the senior guy&#039;s money at risk is a good way to signal and ensure quality.  

The model only works if  owners have real skin in the game:  give them an option (e.g. LLC protection on the downside,) and they will lever to the max.</description>
		<content:encoded><![CDATA[<p>Mark,</p>
<p>as you note, 1 and 3 are the easy ones.</p>
<p>#1 basically killed Wall St.  Once you switch from a partnertship to a LLC, the game is over:  yes, increased access to capital markets lets you do bigger deals, but 1) the compensation time-horizon shrinks from 30+ years to 5 years or so, and 2) the people at risk become a diffuse pool.</p>
<p>Without a pool of 1000 or so of partners and limited partners (the retired MDs,) it&#8217;s all too obvious what happens next:  people lever the one big asset (firm reputation,)  and make great returns for a decade.  Which brings us to point#3:</p>
<p>Few people were trying to be evil, they just optimized given the structure in place.  GS, for example, lined up a $40 billion short-term credit facility:  seemed prudent and conservative.  Then they paid their top producers really well:  again, very reasonable, theys guys made the money for the firm.</p>
<p>But the firm completely missed where the real risk was:  you can&#8217;t lever reputation!  Traditionally, most partnerships fall into one of  four categories:  doctors, laywers, accountants, and investment banks:  all charge high fees because the service is opaque and thus putting the senior guy&#8217;s money at risk is a good way to signal and ensure quality.  </p>
<p>The model only works if  owners have real skin in the game:  give them an option (e.g. LLC protection on the downside,) and they will lever to the max.</p>
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	<item>
		<title>By: themis</title>
		<link>http://www.ritholtz.com/blog/2008/12/how-software-models-doomed-the-markets/comment-page-1/#comment-133337</link>
		<dc:creator>themis</dc:creator>
		<pubDate>Sun, 14 Dec 2008 23:03:44 +0000</pubDate>
		<guid isPermaLink="false">http://www.ritholtz.com/blog/?p=10482#comment-133337</guid>
		<description>As debreuil points out, the software itself might be loaded with defects.
From http://thedailywtf.com/Articles/The-Great-Excel-Spreadsheet.aspx 

----

In going back previous editions of the spreadsheet, somehow, they managed to send completely idiotic numbers to their customers for three full years (at least). Not a single customer, not a single manager ever noticed the inconsistency for what were supposed to be trivial multiplications; not a single one of them noticed that &quot;The-most-important-figure-on-this-chart-we-base-all-our-decisions-on&quot; was random garbage.

In the end, he found out that whenever Helen needed to create a new row, she would simply copy and paste some random row and then adjust the values. At some point, however, she must have messed up and the spreadsheet ended up in a weird state, with formulas referring to cells in other rows, or sometimes even referring to nothing, creating a whole bunch of inconsistent values.

Excited at the chance to clear his name, Maxim revealed his findings to the lead analyst.  However, instead of relief, he only shrugged and responded “Hmph... well, we usually just use our gut for recommendations, anyway.&quot;</description>
		<content:encoded><![CDATA[<p>As debreuil points out, the software itself might be loaded with defects.<br />
From <a href="http://thedailywtf.com/Articles/The-Great-Excel-Spreadsheet.aspx" rel="nofollow">http://thedailywtf.com/Articles/The-Great-Excel-Spreadsheet.aspx</a> </p>
<p>&#8212;-</p>
<p>In going back previous editions of the spreadsheet, somehow, they managed to send completely idiotic numbers to their customers for three full years (at least). Not a single customer, not a single manager ever noticed the inconsistency for what were supposed to be trivial multiplications; not a single one of them noticed that &#8220;The-most-important-figure-on-this-chart-we-base-all-our-decisions-on&#8221; was random garbage.</p>
<p>In the end, he found out that whenever Helen needed to create a new row, she would simply copy and paste some random row and then adjust the values. At some point, however, she must have messed up and the spreadsheet ended up in a weird state, with formulas referring to cells in other rows, or sometimes even referring to nothing, creating a whole bunch of inconsistent values.</p>
<p>Excited at the chance to clear his name, Maxim revealed his findings to the lead analyst.  However, instead of relief, he only shrugged and responded “Hmph&#8230; well, we usually just use our gut for recommendations, anyway.&#8221;</p>
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	<item>
		<title>By: danm</title>
		<link>http://www.ritholtz.com/blog/2008/12/how-software-models-doomed-the-markets/comment-page-1/#comment-133328</link>
		<dc:creator>danm</dc:creator>
		<pubDate>Sun, 14 Dec 2008 22:03:32 +0000</pubDate>
		<guid isPermaLink="false">http://www.ritholtz.com/blog/?p=10482#comment-133328</guid>
		<description>It&#039; s very simple, in portfolio management risk measures are based on volatility.  More often than not, models use 3 years worth of data.  While MPT clearly states expected risk and returns, portfolio managers use historical data.

Most models would have told a portfolio manager who was at 0% in Nortel when the stock was at 120$ that he was being reckless.

I rest my case.</description>
		<content:encoded><![CDATA[<p>It&#8217; s very simple, in portfolio management risk measures are based on volatility.  More often than not, models use 3 years worth of data.  While MPT clearly states expected risk and returns, portfolio managers use historical data.</p>
<p>Most models would have told a portfolio manager who was at 0% in Nortel when the stock was at 120$ that he was being reckless.</p>
<p>I rest my case.</p>
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		<title>By: Mark E Hoffer</title>
		<link>http://www.ritholtz.com/blog/2008/12/how-software-models-doomed-the-markets/comment-page-1/#comment-133322</link>
		<dc:creator>Mark E Hoffer</dc:creator>
		<pubDate>Sun, 14 Dec 2008 21:20:08 +0000</pubDate>
		<guid isPermaLink="false">http://www.ritholtz.com/blog/?p=10482#comment-133322</guid>
		<description>gorobei, fire away until BR comes by w/ the buckets..

2. and 4. are prob. the 200-level ones, out of that bunch, the other two are more readily accessible.

as a +, they&#039;ll lend insight into the &#039;brittleness&#039; of the pricing edifice..</description>
		<content:encoded><![CDATA[<p>gorobei, fire away until BR comes by w/ the buckets..</p>
<p>2. and 4. are prob. the 200-level ones, out of that bunch, the other two are more readily accessible.</p>
<p>as a +, they&#8217;ll lend insight into the &#8216;brittleness&#8217; of the pricing edifice..</p>
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