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> <channel><title>Comments on: My TIPS, Treasuries, and Inflation Model</title> <atom:link href="http://alephblog.com/2009/12/23/my-tips-treasuries-and-inflation-model/feed/" rel="self" type="application/rss+xml" /><link>http://alephblog.com/2009/12/23/my-tips-treasuries-and-inflation-model/</link> <description>Helping Institutions and Ordinary People Invest Better by Focusing on Risk Control</description> <lastBuildDate>Sun, 12 Feb 2012 22:02:53 +0000</lastBuildDate> <sy:updatePeriod>hourly</sy:updatePeriod> <sy:updateFrequency>1</sy:updateFrequency> <generator>http://wordpress.org/?v=3.3.1</generator> <item><title>By: David Merkel</title><link>http://alephblog.com/2009/12/23/my-tips-treasuries-and-inflation-model/comment-page-1/#comment-24038</link> <dc:creator>David Merkel</dc:creator> <pubDate>Wed, 30 Dec 2009 06:15:43 +0000</pubDate> <guid
isPermaLink="false">http://alephblog.com/?p=2236#comment-24038</guid> <description>Eddy, a/alpha (aleph) should be close to zero as the overnight rate in the present environment.  Sadly, it is lower than that, because of the liquidity flood.</description> <content:encoded><![CDATA[<p>Eddy, a/alpha (aleph) should be close to zero as the overnight rate in the present environment.  Sadly, it is lower than that, because of the liquidity flood.</p> ]]></content:encoded> </item> <item><title>By: David Merkel</title><link>http://alephblog.com/2009/12/23/my-tips-treasuries-and-inflation-model/comment-page-1/#comment-24037</link> <dc:creator>David Merkel</dc:creator> <pubDate>Wed, 30 Dec 2009 05:00:51 +0000</pubDate> <guid
isPermaLink="false">http://alephblog.com/?p=2236#comment-24037</guid> <description>c/gamma was negative as I listed it for nominals above, and I commented in my last post that gamma was usually negative, yes.</description> <content:encoded><![CDATA[<p>c/gamma was negative as I listed it for nominals above, and I commented in my last post that gamma was usually negative, yes.</p> ]]></content:encoded> </item> <item><title>By: Eddy Elfenbein</title><link>http://alephblog.com/2009/12/23/my-tips-treasuries-and-inflation-model/comment-page-1/#comment-24036</link> <dc:creator>Eddy Elfenbein</dc:creator> <pubDate>Wed, 30 Dec 2009 04:42:19 +0000</pubDate> <guid
isPermaLink="false">http://alephblog.com/?p=2236#comment-24036</guid> <description>This is a great piece. Thanks for posting it. I would add is that theoretically, the coupon yield is related to the zero yield: e^r = zero rate
If you have a chance, I would be curious is that holds.</description> <content:encoded><![CDATA[<p>This is a great piece. Thanks for posting it. I would add is that theoretically, the coupon yield is related to the zero yield: e^r = zero rate</p><p>If you have a chance, I would be curious is that holds.</p> ]]></content:encoded> </item> <item><title>By: Peter</title><link>http://alephblog.com/2009/12/23/my-tips-treasuries-and-inflation-model/comment-page-1/#comment-24032</link> <dc:creator>Peter</dc:creator> <pubDate>Wed, 30 Dec 2009 00:25:41 +0000</pubDate> <guid
isPermaLink="false">http://alephblog.com/?p=2236#comment-24032</guid> <description>Duh, should have known that one :-)
This form makes it much clearer. Thx. Now shouldn&#039;t the c/gamma variable in the inflation model then be negative as well?</description> <content:encoded><![CDATA[<p>Duh, should have known that one <img
src='http://alephblog.com/wp-includes/images/smilies/icon_smile.gif' alt=':-)' class='wp-smiley' /></p><p>This form makes it much clearer. Thx. Now shouldn&#8217;t the c/gamma variable in the inflation model then be negative as well?</p> ]]></content:encoded> </item> <item><title>By: David Merkel</title><link>http://alephblog.com/2009/12/23/my-tips-treasuries-and-inflation-model/comment-page-1/#comment-23996</link> <dc:creator>David Merkel</dc:creator> <pubDate>Fri, 25 Dec 2009 16:26:40 +0000</pubDate> <guid
isPermaLink="false">http://alephblog.com/?p=2236#comment-23996</guid> <description>Here&#039;s the equation:
&lt;a href=&quot;http://alephblog.com/wp-content/uploads/2009/12/yt.gif&quot; rel=&quot;nofollow&quot;&gt;&lt;img class=&quot;alignnone&quot; title=&quot;The Equation&quot; src=&quot;http://alephblog.com/wp-content/uploads/2009/12/yt.gif&quot; alt=&quot;&quot; width=&quot;170&quot; height=&quot;15&quot; /&gt;&lt;/a&gt;&lt;/p&gt;
This is the way I have written the from the beginning.  I said a, b, c, and w before -- originally they were alpha, beta, gamma and omega.  It is a remarkably flexible functional form, and parsimonious.  If omega is one (rare), beta and gamma become the prices for duration and convexity.  Alpha is the overnight rate.  Since omega is usually not one, I call beta and gamma the prices of pseudo-duration and pseudo-convexity.  Under ordinary circumstances, for nominal rates, alpha, beta and omega are positive, and gamma negative.
Things are not normal for alpha now, given the government flooding the system with liquidity.  Alpha would go more negative if I did not constrain spot rates after three months to be positive.  I would get a better fit, but I have a hard time thinking that model is working right if I let spot rates get negative too far out.
The omega variable is what makes the functional form so flexible.  It also means that the parameters can no longer be estimated through regression, but must be solved using nonlinear optimization (in Excel, using solver).
The raw data for the model is nominal Treasury note and bond, and TIPS prices.  I minimize the squared error between the actual prices, and the hypothetical prices generated by discounting the cash flows of the bonds from the yields generated from the four-factor equation above.  A second four-factor equation of the same form drives forward inflation estimates, and thus cash flows on the TIPS.
So, there are eight variables for this model.  It&#039;s a parsimonious system that explains a lot, and looks reasonable.</description> <content:encoded><![CDATA[<p>Here&#8217;s the equation:</p><p><a
href="http://alephblog.com/wp-content/uploads/2009/12/yt.gif" rel="nofollow"><img
class="alignnone" src="http://alephblog.com/wp-content/uploads/2009/12/yt.gif" alt="" width="170" height="15" /></a></p><p>This is the way I have written the from the beginning.  I said a, b, c, and w before &#8212; originally they were alpha, beta, gamma and omega.  It is a remarkably flexible functional form, and parsimonious.  If omega is one (rare), beta and gamma become the prices for duration and convexity.  Alpha is the overnight rate.  Since omega is usually not one, I call beta and gamma the prices of pseudo-duration and pseudo-convexity.  Under ordinary circumstances, for nominal rates, alpha, beta and omega are positive, and gamma negative.</p><p>Things are not normal for alpha now, given the government flooding the system with liquidity.  Alpha would go more negative if I did not constrain spot rates after three months to be positive.  I would get a better fit, but I have a hard time thinking that model is working right if I let spot rates get negative too far out.</p><p>The omega variable is what makes the functional form so flexible.  It also means that the parameters can no longer be estimated through regression, but must be solved using nonlinear optimization (in Excel, using solver).</p><p>The raw data for the model is nominal Treasury note and bond, and TIPS prices.  I minimize the squared error between the actual prices, and the hypothetical prices generated by discounting the cash flows of the bonds from the yields generated from the four-factor equation above.  A second four-factor equation of the same form drives forward inflation estimates, and thus cash flows on the TIPS.</p><p>So, there are eight variables for this model.  It&#8217;s a parsimonious system that explains a lot, and looks reasonable.</p> ]]></content:encoded> </item> <item><title>By: David Merkel</title><link>http://alephblog.com/2009/12/23/my-tips-treasuries-and-inflation-model/comment-page-1/#comment-23993</link> <dc:creator>David Merkel</dc:creator> <pubDate>Fri, 25 Dec 2009 05:17:29 +0000</pubDate> <guid
isPermaLink="false">http://alephblog.com/?p=2236#comment-23993</guid> <description>Shiv and brendo -- I will have a post on that soon.
David C. -- I might have a copy of the paper somewhere in my basement.  If I find it, I could scan it.  My problem is getting the time to look for it.  If you have the formula that I listed, you have the &quot;money shot&quot; of the paper.
There are two sets of a, b, c, and w.  One for nominal Treasury rates, and the other for inflation.  Eight parameters in all.
What was the data?  Bond prices, coupons, and maturities and time.  The idea was to estimate interest rates and implied inflation rates from the prices of Treasury securities versus their cash flows.</description> <content:encoded><![CDATA[<p>Shiv and brendo &#8212; I will have a post on that soon.</p><p>David C. &#8212; I might have a copy of the paper somewhere in my basement.  If I find it, I could scan it.  My problem is getting the time to look for it.  If you have the formula that I listed, you have the &#8220;money shot&#8221; of the paper.</p><p>There are two sets of a, b, c, and w.  One for nominal Treasury rates, and the other for inflation.  Eight parameters in all.</p><p>What was the data?  Bond prices, coupons, and maturities and time.  The idea was to estimate interest rates and implied inflation rates from the prices of Treasury securities versus their cash flows.</p> ]]></content:encoded> </item> <item><title>By: David C.</title><link>http://alephblog.com/2009/12/23/my-tips-treasuries-and-inflation-model/comment-page-1/#comment-23983</link> <dc:creator>David C.</dc:creator> <pubDate>Fri, 25 Dec 2009 01:40:50 +0000</pubDate> <guid
isPermaLink="false">http://alephblog.com/?p=2236#comment-23983</guid> <description>Secondly, how many free parameters are in the model? Are the a, b, c, w coefficients estimated from some other numerical procedure (by actually computing convexity from some other dataset)? You mentioned that you used a nonlinear fit, which is fine, but did not specify which variables are free in this fitting procedure.</description> <content:encoded><![CDATA[<p>Secondly, how many free parameters are in the model? Are the a, b, c, w coefficients estimated from some other numerical procedure (by actually computing convexity from some other dataset)? You mentioned that you used a nonlinear fit, which is fine, but did not specify which variables are free in this fitting procedure.</p> ]]></content:encoded> </item> <item><title>By: David C.</title><link>http://alephblog.com/2009/12/23/my-tips-treasuries-and-inflation-model/comment-page-1/#comment-23982</link> <dc:creator>David C.</dc:creator> <pubDate>Fri, 25 Dec 2009 01:38:02 +0000</pubDate> <guid
isPermaLink="false">http://alephblog.com/?p=2236#comment-23982</guid> <description>I have been searching for this paper and found a citation for
S. Diller, &quot;The yield surface - a three dimensional approach relating yield to duration and convexity, Bear Stearns, fixed income strategies&quot; February, New York
Is there any way we can get a copy of this paper? It doesn&#039;t appear to be published in any journals I can find.</description> <content:encoded><![CDATA[<p>I have been searching for this paper and found a citation for</p><p>S. Diller, &#8220;The yield surface &#8211; a three dimensional approach relating yield to duration and convexity, Bear Stearns, fixed income strategies&#8221; February, New York</p><p>Is there any way we can get a copy of this paper? It doesn&#8217;t appear to be published in any journals I can find.</p> ]]></content:encoded> </item> <item><title>By: brendo</title><link>http://alephblog.com/2009/12/23/my-tips-treasuries-and-inflation-model/comment-page-1/#comment-23972</link> <dc:creator>brendo</dc:creator> <pubDate>Thu, 24 Dec 2009 17:53:57 +0000</pubDate> <guid
isPermaLink="false">http://alephblog.com/?p=2236#comment-23972</guid> <description>Hi David...very neat analysis!  Do you have a book that you would recommend to buy off amazon (link off your site) that explains the forward curve/negative curves/ basically understand how bonds affect prices?
Merry X-mas</description> <content:encoded><![CDATA[<p>Hi David&#8230;very neat analysis!  Do you have a book that you would recommend to buy off amazon (link off your site) that explains the forward curve/negative curves/ basically understand how bonds affect prices?<br
/> Merry X-mas</p> ]]></content:encoded> </item> <item><title>By: Shiv Desai</title><link>http://alephblog.com/2009/12/23/my-tips-treasuries-and-inflation-model/comment-page-1/#comment-23969</link> <dc:creator>Shiv Desai</dc:creator> <pubDate>Thu, 24 Dec 2009 05:48:15 +0000</pubDate> <guid
isPermaLink="false">http://alephblog.com/?p=2236#comment-23969</guid> <description>Hi David,
I am a CFA candidate and would like to learn quantitative techniques in detail, that are used in Investment Decision Making. Could you please suggest some books that covers relevant areas??
Please Reply.
With Regards,</description> <content:encoded><![CDATA[<p>Hi David,</p><p>I am a CFA candidate and would like to learn quantitative techniques in detail, that are used in Investment Decision Making. Could you please suggest some books that covers relevant areas??</p><p>Please Reply.</p><p>With Regards,</p> ]]></content:encoded> </item> </channel> </rss>
