Default Model

<body onLoad="MM_checkPlugin('Shockwave Flash','','http://www.riskglossary.com/default_nofl.htm',false);return document.MM_returnValue" stylesrc="../_private/template.htm" bgcolor="#FFFFFF" link="#669933" vlink="#000000" alink="#000000"> <div align="left"> <table border="0" cellpadding="0" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="100%" id="table1"> <tr> <td width="740"> <table border="0" cellpadding="0" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="100%" height="37" id="table2"> <tr> <td height="35" width="100%"> <table border="0" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="100%" cellpadding="0" id="table3"> <tr> <td width="100%" align="left" valign="top"> <p class="header_gold">Default Model</td> <td width="45" align="right" valign="bottom"> <map name="FPMap6"> <area href="http://www.contingencyanalysis.com" shape="rect" coords="1, 0, 44, 11" target="_top"> </map> <img border="0" src="../images/home.gif" usemap="#FPMap6" width="45" height="12"></td> </tr> </table> </td> </tr> <tr> <td width="100%" bgcolor="#CC9966" height="2"> <img border="0" src="../images/blank_2x2.gif" width="2" height="2"></td> </tr> <tr> <td width="0%" valign="top" bgcolor="#FFFFCC"> <table border="0" style="border-collapse: collapse" bordercolor="#111111" width="100%" cellpadding="0" cellspacing="1" id="table4"> <tr> <td width="0%" align="left" valign="top"> <p class="header2_black">Explained:<br> <img border="0" src="../images/blank_1x100.gif" width="100" height="1"></td> <td width="0%" align="left" valign="top"><p class="word_list"> <a href="#Default models">default model</a><p class="word_list"> <a href="#exposure at default">exposure at default</a><p class="word_list"> <a href="#loss given default">loss given default</a><br> <img border="0" src="../images/blank_1x160.gif" width="160" height="1"></td> <td width="100%" align="left" valign="top"><p class="word_list"> <a href="#ratings migration models">ratings migration model</a><p class="word_list"> <a href="#ratings transition matrix">ratings transition matrix</a><br> <img border="0" src="../images/blank_1x160.gif" width="160" height="1"></td> </tr> </table> </td> </tr> </table> <p class="body"><b><a name="Default models">Default models</a></b> are a category of models that assess the likelihood of default by an <a href="../articles/credit_risk.htm">obligor</a>. They differ from <a href="../articles/credit_risk.htm">credit scoring</a> models in two ways:</p> <table border="0" cellpadding="0" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="160" align="right" id="table5"> <tr> <td>  <script type="text/javascript"></script> <script type="text/javascript" src="http://pagead2.googlesyndication.com/pagead/show_ads.js"> </script> </td> </tr> </table> <p class="body"><img border="0" src="../images/bullet.gif" width="20" height="10">Credit scoring is usually (but not always) applied to smaller <a href="../articles/credit_risk.htm">credits</a>—individuals or small businesses. Default models are applied more to larger credits—<a href="../articles/corporation.htm">corporation</a> or sovereigns.</p> <p class="body"><img border="0" src="../images/bullet.gif" width="20" height="10">Credit scoring models are largely statistical, regressing instances of default against various risk indicators, such as a obligor's income, home renter/owner status, etc. Default models directly model the default process, and are typically calibrated to market variables, such as the obligor's <a href="../articles/common_stock.htm">stock</a> price or the <a href="../articles/interest_rate_spreads.htm">credit spread</a> on its <a href="../articles/coupon_bond.htm">bonds</a>.</p> <p class="body">Default models find many applications within financial institutions. They are used</p> <p class="bullet_line_space" style="margin-top: 10; margin-bottom: 10"> <img border="0" src="../images/bullet.gif" width="20" height="10">to support or supplant <a href="../articles/credit_risk.htm">credit analysis</a>;</p> <p class="bullet_line_space" style="margin-top: 10; margin-bottom: 10"> <img border="0" src="../images/bullet.gif" width="20" height="10">to calculate utilization of counterparty credit <a href="../articles/risk_limits.htm">risk limits</a>;</p> <p class="bullet_line_space" style="margin-top: 10; margin-bottom: 10"> <img border="0" src="../images/bullet.gif" width="20" height="10">to extend standard <a href="../articles/option_pricing_theory.htm">financial engineering</a> techniques to value <a href="../articles/credit_derivative.htm">credit derivatives</a> or other credit sensitive instruments.</p> <p class="body">Default models may be integrated with some sort of <a href="../articles/correlation.htm">correlation</a> model to facilitate modeling the credit risk of portfolios with exposures to multiple obligors. Such extensions of default models—called <a href="../articles/portfolio_credit_risk.htm">portfolio credit risk models</a>—can be used</p> <p class="bullet_line_space" style="margin-top: 10; margin-bottom: 10"> <img border="0" src="../images/bullet.gif" width="20" height="10">to calculate utilization of industry, country or portfolio credit risk limits;</p> <p class="bullet_line_space" style="margin-top: 10; margin-bottom: 10"> <img border="0" src="../images/bullet.gif" width="20" height="10">to price <a href="../articles/collateralized_debt_obligation.htm">collateralized debt obligations</a> (CDOs) or other <a href="../articles/securitization.htm">securitizations</a>;</p> <p class="bullet_line_space" style="margin-top: 10; margin-bottom: 10"> <img border="0" src="../images/bullet.gif" width="20" height="10">to support <a href="../articles/capital_allocation.htm">capital</a> calculations.</p> <p class="body">Consider a time horizon staring at the current time 0 and ending at some future time <i>t</i>. A one year horizon is typical, but financial institutions usually consider credit risk over several horizons. Let <i>L</i> represent the financial loss, if any, due to default on a particular obligation—a bond, loan, <a href="../articles/derivative_instrument.htm">derivative instrument</a>, etc.—over the horizon. <i>L</i> is a random variable. Its <a href="../articles/mean.htm">expected value</a> <i>E</i>(<i>L</i>) is a <a href="../articles/risk_metric_and_risk_measure.htm">metric</a> of the credit risk of the obligation. It can be calculated as the <a name="[1]"> product</a></p> <table border="0" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="100%" cellpadding="0" height="36" id="table6"> <tr> <td width="100%" align="center"> <i>E</i>(<i>L</i>) = <i>Pr</i>(default) EAD LGD</td> <td width="5%" align="right">[1]</td> </tr> </table> <table border="0" cellpadding="0" style="border-collapse: collapse" bordercolor="#111111" width="310" align="left" id="table7"> <tr> <td width="300" height="14"><font size="2"> </font><font size="4"> </font></td> <td width="9" height="14"></td> </tr> <tr> <td width="300"> <script type="text/javascript"></script> <script type="text/javascript" src="http://pagead2.googlesyndication.com/pagead/show_ads.js"> </script>  </td> <td width="9"> </td> </tr> </table> <p class="body">where</p> <p class="bullet_line_space"><img border="0" src="../images/bullet.gif" width="20" height="10"><i>Pr</i>(default) is the probability of default on the obligation during the horizon—what is called the <a href="../articles/credit_risk.htm">default probability</a>.</p> <p class="bullet_line_space"><img border="0" src="../images/bullet.gif" width="20" height="10">EAD is <b><a name="exposure at default"> exposure at default</a></b>—the <a href="../articles/credit_risk.htm"> credit exposure</a> on the obligation at the time of default. In [<a href="#[1]">1</a>], this is treated as a known constant. </p> <p class="bullet_line_space"><img border="0" src="../images/bullet.gif" width="20" height="10">LGD is <b><a name="loss given default">loss given default</a></b>—the fraction of EAD that will not be recovered following default. EAD is simply 1 minus the <a href="../articles/credit_risk.htm">recovery rate</a>. In [<a href="#[1]">1</a>], it too is treated as a known constant.</p> <p class="body">The essential purpose of a default model is to calculate the default probability. However, sophisticated models may do more than this. For example, models might treat EAD and LGD as random, and substitute their expectations into [<a href="#[1]">1</a>]. Treating both in this manner requires an assumption that they are independent. Such an assumption is difficult to justify, but it may be made to simplify models.</p> <p class="body">A simple default model can be constructed by calibrating <a href="../articles/credit_risk.htm">credit ratings</a> to historical frequencies of migrations between ratings. Exhibit 1 indicates a <b><a name="ratings transition matrix">ratings transition matrix</a></b>. constructed by Standard & Poor's. It indicates one-year ratings migration probabilities based upon bond rating data from the period 1981-2000. </p> <div align="center"> <center> <table border="0" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="450" cellpadding="0" id="table8"> <tr> <td> <p class="exhibit_header"><span class="exhibit_header">One-Year Ratings Transition Matrix</span><br> <span class="exhibit_subheader">Exhibit 1</span></td> </tr> <tr> <td bgcolor="#CC9966" height="2"> <img border="0" src="../images/blank_2x2.gif" width="2" height="2"></td> </tr> <tr> <td> <div align="center"> <center> <table border="0" cellpadding="4" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="95%" class="explanatory_text" id="table9"> <tr> <td width="12%" style="border-right: 1px solid #CC9966; border-bottom: 1px solid #CC9966" bgcolor="#FFFFCC" rowspan="2" align="center"> <b>original rating</b></td> <td width="88%" bgcolor="#FFFFCC" colspan="8" height="25" align="center" valign="top"> <p align="center"><b>probability of migrating to rating by year end (%)</b></td> </tr> <tr> <td width="11%" style="border-bottom: 1px solid #CC9966" bgcolor="#FFFFCC" align="center"> <span style="background-color: #FFFFCC">AAA</span></td> <td width="11%" style="border-bottom: 1px solid #CC9966" bgcolor="#FFFFCC" align="center"> <span style="background-color: #FFFFCC">AA</span></td> <td width="11%" style="border-bottom: 1px solid #CC9966" bgcolor="#FFFFCC" align="center"> <span style="background-color: #FFFFCC">A</span></td> <td width="11%" style="border-bottom: 1px solid #CC9966" bgcolor="#FFFFCC" align="center"> <span style="background-color: #FFFFCC">BBB</span></td> <td width="11%" style="border-bottom: 1px solid #CC9966" bgcolor="#FFFFCC" align="center"> <span style="background-color: #FFFFCC">BB</span></td> <td width="11%" style="border-bottom: 1px solid #CC9966" bgcolor="#FFFFCC" align="center"> <span style="background-color: #FFFFCC">B</span></td> <td width="11%" style="border-bottom: 1px solid #CC9966" bgcolor="#FFFFCC" align="center"> <span style="background-color: #FFFFCC">CCC</span></td> <td width="11%" style="border-bottom: 1px solid #CC9966" bgcolor="#FFFFCC" align="center"> <span style="background-color: #FFFFCC">Default</span></td> </tr> <tr> <td width="12%" style="border-right: 1px solid #CC9966" bgcolor="#FFFFCC"> AAA</td> <td width="11%" align="right">93.66</td> <td width="11%" align="right">5.83</td> <td width="11%" align="right">0.40</td> <td width="11%" align="right">0.08</td> <td width="11%" align="right">0.03</td> <td width="11%" align="right">0.00</td> <td width="11%" align="right">0.00</td> <td width="11%" align="right">0.00</td> </tr> <tr> <td width="12%" style="border-right: 1px solid #CC9966" bgcolor="#FFFFCC"> AA</td> <td width="11%" align="right">0.66</td> <td width="11%" align="right">91.72</td> <td width="11%" align="right">6.94</td> <td width="11%" align="right">0.49</td> <td width="11%" align="right">0.06</td> <td width="11%" align="right">0.09</td> <td width="11%" align="right">0.02</td> <td width="11%" align="right">0.01</td> </tr> <tr> <td width="12%" style="border-right: 1px solid #CC9966" bgcolor="#FFFFCC"> A</td> <td width="11%" align="right">0.07</td> <td width="11%" align="right">2.25</td> <td width="11%" align="right">91.76</td> <td width="11%" align="right">5.19</td> <td width="11%" align="right">0.49</td> <td width="11%" align="right">0.20</td> <td width="11%" align="right">0.01</td> <td width="11%" align="right">0.04</td> </tr> <tr> <td width="12%" style="border-right: 1px solid #CC9966" bgcolor="#FFFFCC"> BBB</td> <td width="11%" align="right">0.03</td> <td width="11%" align="right">0.25</td> <td width="11%" align="right">4.83</td> <td width="11%" align="right">89.26</td> <td width="11%" align="right">4.44</td> <td width="11%" align="right">0.81</td> <td width="11%" align="right">0.16</td> <td width="11%" align="right">0.22</td> </tr> <tr> <td width="12%" style="border-right: 1px solid #CC9966" bgcolor="#FFFFCC"> BB</td> <td width="11%" align="right">0.03</td> <td width="11%" align="right">0.07</td> <td width="11%" align="right">0.44</td> <td width="11%" align="right">6.67</td> <td width="11%" align="right">83.31</td> <td width="11%" align="right">7.47</td> <td width="11%" align="right">1.05</td> <td width="11%" align="right">0.98</td> </tr> <tr> <td width="12%" style="border-right: 1px solid #CC9966" bgcolor="#FFFFCC"> B</td> <td width="11%" align="right">0.00</td> <td width="11%" align="right">0.10</td> <td width="11%" align="right">0.33</td> <td width="11%" align="right">0.46</td> <td width="11%" align="right">5.77</td> <td width="11%" align="right">84.19</td> <td width="11%" align="right">3.87</td> <td width="11%" align="right">5.30</td> </tr> <tr> <td width="12%" style="border-right: 1px solid #CC9966" bgcolor="#FFFFCC"> CCC</td> <td width="11%" align="right">0.16</td> <td width="11%" align="right">0.00</td> <td width="11%" align="right">0.31</td> <td width="11%" align="right">0.93</td> <td width="11%" align="right">2.00</td> <td width="11%" align="right">10.74</td> <td width="11%" align="right">63.96</td> <td width="11%" align="right">21.94</td> </tr> <tr> <td width="12%" style="border-right: 1px solid #CC9966" bgcolor="#FFFFCC"> Default</td> <td width="11%" align="right">0.00</td> <td width="11%" align="right">0.00</td> <td width="11%" align="right">0.00</td> <td width="11%" align="right">0.00</td> <td width="11%" align="right">0.00</td> <td width="11%" align="right">0.00</td> <td width="11%" align="right">0.00</td> <td width="11%" align="right">100.00</td> </tr> </table> </center> </div> </td> </tr> <tr> <td> <p class="exhibit_legend">One-year ratings migration probabilities based upon bond rating data from 1981-2000. Data is adjusted for rating withdrawals. Numbers in each row should sum to 100%. Due to round-off error, they may not do so exactly. Source: Standard & Poor's.</td> </tr> </table> </center> </div> <table border="0" cellpadding="0" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="345" align="right" id="table10"> <tr> <td align="right" width="9" height="10"></td> <td width="336" height="10"> <font size="2"> </font></td> </tr> <tr> <td align="right" width="9"> </td> <td width="336">  <p style="margin-top: 0; margin-bottom: 2" class="ad_legend"> <a target="_top" href="http://www.riskexpertise.com/link/advertising.htm"> <font color="#000000">Ads by Contingency Analysis</font></a></p> <p style="margin-top: 0; margin-bottom: 0"> <iframe src="http://servedbyadbutler.com/adserve/;ID=147917;size=336x265;setID=82402;type=iframe" style="margin: 0px; padding: 0px; border-width: 0px" width="336" height="265" frameborder="0" marginwidth="0" marginheight="0" scrolling="no" name="I1"> <![if lt IE 4]> <script src="http://servedbyadbutler.com/adserve/;ID=147917;size=336x265;setID=82402;type=js" type="text/javascript"> </script> <noscript> <a href="http://servedbyadbutler.com/go2/;ID=147917;size=336x265;setID=82402"> <img src="http://servedbyadbutler.com/adserve.ibs/;ID=147917;size=336x265;setID=82402;type=img" border="0" height="265" width="336" alt=""></a> </noscript><![endif]></iframe>   </td> </tr> </table> <p class="body">For example, based upon the matrix, a BBB-rated bond has a 4.44% probability of being downgraded to a BB-rating by the end of one year. The matrix is based upon raw data, so it exhibits statistical anomalies. A CCC-rated bond is given a 0.16% probability of being upgraded to AAA, but a B-rated bond has a 0.00% probability of such an upgrade. If it were used to model defaults, the numbers in the matrix might be smoothed.</p> <p class="body">To use a ratings transition matrix as a default model, we simply take the default probabilities indicated in the last column and ascribe them to bonds of the corresponding credit ratings. For example, with this approach, we would ascribe an A-rated bond a 0.04% probability of default within one year.</p> <p class="body">If we want two-year default probabilities, we simply multiply the matrix by itself once (i.e. employ matrix multiplication as defined in linear algebra) to obtain a two-year ratings transition matrix. The last column of that matrix will provide the desired default probabilities. For three-year default probabilities, we multiply the matrix by itself three times, etc. Exhibit 2 indicates a five-year ratings transition matrix obtained by multiplying the one-year matrix of Exhibit 1 by itself five times.</p> <div align="center"> <center> <table border="0" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="450" cellpadding="0" id="table11"> <tr> <td> <p class="exhibit_header"><span class="exhibit_header">Five-Year Ratings Transition Matrix</span><br> <span class="exhibit_subheader">Exhibit 2</span></td> </tr> <tr> <td bgcolor="#CC9966" height="2"> <img border="0" src="../images/blank_2x2.gif" width="2" height="2"></td> </tr> <tr> <td> <div align="center"> <center> <table border="0" cellpadding="4" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="95%" class="explanatory_text" id="table12"> <tr> <td width="12%" style="border-right: 1px solid #CC9966; border-bottom: 1px solid #CC9966" bgcolor="#FFFFCC" rowspan="2" align="center"> <b>original rating</b></td> <td width="88%" bgcolor="#FFFFCC" colspan="8" height="25" align="center" valign="top"> <p align="center"><b>probability of rating after five years (percent)</b></td> </tr> <tr> <td width="11%" style="border-bottom: 1px solid #CC9966" bgcolor="#FFFFCC" align="center"> <span style="background-color: #FFFFCC">AAA</span></td> <td width="11%" style="border-bottom: 1px solid #CC9966" bgcolor="#FFFFCC" align="center"> <span style="background-color: #FFFFCC">AA</span></td> <td width="11%" style="border-bottom: 1px solid #CC9966" bgcolor="#FFFFCC" align="center"> <span style="background-color: #FFFFCC">A</span></td> <td width="11%" style="border-bottom: 1px solid #CC9966" bgcolor="#FFFFCC" align="center"> <span style="background-color: #FFFFCC">BBB</span></td> <td width="11%" style="border-bottom: 1px solid #CC9966" bgcolor="#FFFFCC" align="center"> <span style="background-color: #FFFFCC">BB</span></td> <td width="11%" style="border-bottom: 1px solid #CC9966" bgcolor="#FFFFCC" align="center"> <span style="background-color: #FFFFCC">B</span></td> <td width="11%" style="border-bottom: 1px solid #CC9966" bgcolor="#FFFFCC" align="center"> <span style="background-color: #FFFFCC">CCC</span></td> <td width="11%" style="border-bottom: 1px solid #CC9966" bgcolor="#FFFFCC" align="center"> <span style="background-color: #FFFFCC">Default</span></td> </tr> <tr> <td width="12%" style="border-right: 1px solid #CC9966" bgcolor="#FFFFCC"> AAA</td> <td width="11%" align="right">72.39</td> <td width="11%" align="right">21.69</td> <td width="11%" align="right">4.74</td> <td width="11%" align="right">0.86</td> <td width="11%" align="right">0.20</td> <td width="11%" align="right">0.08</td> <td width="11%" align="right">0.01</td> <td width="11%" align="right">0.02</td> </tr> <tr> <td width="12%" style="border-right: 1px solid #CC9966" bgcolor="#FFFFCC"> AA</td> <td width="11%" align="right">2.49</td> <td width="11%" align="right">66.45</td> <td width="11%" align="right">25.05</td> <td width="11%" align="right">4.45</td> <td width="11%" align="right">0.75</td> <td width="11%" align="right">0.51</td> <td width="11%" align="right">0.09</td> <td width="11%" align="right">0.18</td> </tr> <tr> <td width="12%" style="border-right: 1px solid #CC9966" bgcolor="#FFFFCC"> A</td> <td width="11%" align="right">0.39</td> <td width="11%" align="right">8.19</td> <td width="11%" align="right">68.22</td> <td width="11%" align="right">18.05</td> <td width="11%" align="right">3.19</td> <td width="11%" align="right">1.32</td> <td width="11%" align="right">0.18</td> <td width="11%" align="right">0.50</td> </tr> <tr> <td width="12%" style="border-right: 1px solid #CC9966" bgcolor="#FFFFCC"> BBB</td> <td width="11%" align="right">0.16</td> <td width="11%" align="right">1.72</td> <td width="11%" align="right">16.80</td> <td width="11%" align="right">60.61</td> <td width="11%" align="right">13.16</td> <td width="11%" align="right">4.68</td> <td width="11%" align="right">0.79</td> <td width="11%" align="right">2.08</td> </tr> <tr> <td width="12%" style="border-right: 1px solid #CC9966" bgcolor="#FFFFCC"> BB</td> <td width="11%" align="right">0.13</td> <td width="11%" align="right">0.53</td> <td width="11%" align="right">3.81</td> <td width="11%" align="right">19.50</td> <td width="11%" align="right">44.77</td> <td width="11%" align="right">19.84</td> <td width="11%" align="right">3.09</td> <td width="11%" align="right">8.34</td> </tr> <tr> <td width="12%" style="border-right: 1px solid #CC9966" bgcolor="#FFFFCC"> B</td> <td width="11%" align="right">0.06</td> <td width="11%" align="right">0.42</td> <td width="11%" align="right">1.62</td> <td width="11%" align="right">4.15</td> <td width="11%" align="right">15.18</td> <td width="11%" align="right">46.97</td> <td width="11%" align="right">6.54</td> <td width="11%" align="right">25.15</td> </tr> <tr> <td width="12%" style="border-right: 1px solid #CC9966" bgcolor="#FFFFCC"> CCC</td> <td width="11%" align="right">0.34</td> <td width="11%" align="right">0.20</td> <td width="11%" align="right">1.21</td> <td width="11%" align="right">3.05</td> <td width="11%" align="right">6.33</td> <td width="11%" align="right">18.10</td> <td width="11%" align="right">12.36</td> <td width="11%" align="right">58.51</td> </tr> <tr> <td width="12%" style="border-right: 1px solid #CC9966" bgcolor="#FFFFCC"> Default</td> <td width="11%" align="right">0.00</td> <td width="11%" align="right">0.00</td> <td width="11%" align="right">0.00</td> <td width="11%" align="right">0.00</td> <td width="11%" align="right">0.00</td> <td width="11%" align="right">0.00</td> <td width="11%" align="right">0.00</td> <td width="11%" align="right">100.00</td> </tr> </table> </center> </div> </td> </tr> <tr> <td> <p class="exhibit_legend">Five-year ratings migration probabilities obtained by multiplying the matrix of Exhibit 1 by itself five times.</td> </tr> </table> </center> </div> <p class="body">Default models that base default probabilities on empirical ratings transition matrices are called <b> <a name="ratings migration models">ratings migration models</a></b>. CreditMetrics is an example of a commercial portfolio credit risk model that calculates default probabilities with a ratings migration model. CreditMetrics also uses its ratings migration matrices to model the evolution of bonds' credit spreads based upon migrations in their ratings. This allows for the modeling of bond portfolios' market (or mark-to-model) values over time.</p> <table border="0" cellpadding="0" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="345" align="right" id="table13"> <tr> <td align="right" width="9" height="10"></td> <td width="336" height="10"> <font size="2"> </font></td> </tr> <tr> <td align="right" width="9"> </td> <td width="336"> <script type="text/javascript"></script> <script type="text/javascript" src="http://pagead2.googlesyndication.com/pagead/show_ads.js"> </script>  </td> </tr> </table> <p class="body">Ratings migration models have a number of shortcomings. First, credit ratings reflect overall <a href="../articles/credit_risk.htm">credit quality</a>, which depends on both probabilities of default as well as likely recovery rates. If two bonds have the same credit rating, but one bond is senior and the other is subordinated, the senior bond is likely to have a higher default probability offsetting its likely higher recovery rate.</p> <p class="body">Second, ratings migration models are not dynamic. Because they are based upon long-term empirical probabilities of ratings transitions, they are not sensitive to business cycles or other fluctuations in the business environment.</p> <p class="body">Ratings migration models are just one type of default model. Many different default models have been proposed in the literature or implemented by financial institutions. With few exceptions, those that are not ratings migration models are implementations of:</p> <p class="bullet"><img border="0" src="../images/bullet.gif" width="20" height="10"><a href="../articles/asset_value_model.htm">asset value models</a>, or</p> <p class="bullet"><img border="0" src="../images/bullet.gif" width="20" height="10"><a href="../articles/intensity_model.htm">intensity models</a>.</p> <p class="body">Both types of models are sophisticated, flexible approaches to credit risk modeling that support a variety of analyses. They can be calibrated to current business conditions (typically using a firm's stock price or bond spreads for this purpose). They can be implemented with "real probabilities" to support credit risk measurement or with <a href="../articles/option_pricing_theory.htm">risk neutral</a> probabilities to support financial engineering applications.</p> <table border="0" cellpadding="0" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="100%" id="table14"> <tr> <td height="30" valign="bottom" colspan="2"> <p class="header2_black">Related Internal Links</td> </tr> <tr> <td colspan="2" bgcolor="#CC9966" height="2"> <img border="0" src="../images/blank_2x2.gif" width="2" height="2"></td> </tr> <tr> <td bgcolor="#FFFFCC" colspan="2"> <table border="0" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="100%" cellpadding="6" id="table15"> <tr> <td width="100%"> <p align="left" class="explanatory_text"> <img border="0" src="../images/bullet_link_glossary.gif" width="26" height="15"><strong style="font-weight: 400"><a href="../articles/asset_value_model.htm">asset value model</a> A type of default model.</strong></p> <p class="explanatory_text"> <img border="0" src="../images/bullet_link_glossary.gif" width="26" height="15"><a href="../articles/credit_derivative.htm">credit derivative</a> A derivative instrument designed to transfer credit risk from one party to another.<p align="left" class="explanatory_text"> <img border="0" src="../images/bullet_link_glossary.gif" width="26" height="15"><strong style="font-weight: 400"><a href="../articles/credit_risk.htm">credit risk</a> Risk</strong> due to uncertainty in a counterparty's ability to meet its obligations.</p> <p align="left" class="explanatory_text"> <img border="0" src="../images/bullet_link_glossary.gif" width="26" height="15"><strong style="font-weight: 400"><a href="../articles/intensity_model.htm">intensity model</a> A type of default model.</strong></p> <p class="explanatory_text"> <img border="0" src="../images/bullet_link_glossary.gif" width="26" height="15"><a href="../articles/portfolio_credit_risk.htm">portfolio credit risk</a> Credit risk associated with a portfolio of obligations, typically of multiple obligors.<p class="explanatory_text"> <img border="0" src="../images/bullet_link_glossary.gif" width="26" height="15"><a href="../articles/presettlement_risk.htm">pre-settlement risk</a> Credit risk of default on a derivative instrument prior to final settlement.</td> </tr> </table> </td> </tr> <tr> <td height="30" valign="bottom" colspan="2"> <p class="header2_black">Sponsored Links</td> </tr> <tr> <td colspan="2" bgcolor="#CC9966" height="2"> <img border="0" src="../images/blank_2x2.gif" width="2" height="2"></td> </tr> <tr> <td bgcolor="#FFFFCC" width="75"> <img border="0" src="../images/ad_side_banner_1.jpg" width="103" height="285"></td> <td bgcolor="#FFFFCC" width="99%">  <p class="ad_legend" style="margin-left: 0; margin-bottom:2"> <a target="_top" href="http://www.riskexpertise.com/link/advertising.htm"> <font color="#000000">Ads by Contingency Analysis</font></a></p> <p style="margin-top: 0; margin-bottom: 0"> <iframe src="http://servedbyadbutler.com/adserve/;ID=147917;size=336x265;setID=82436;type=iframe" style="margin: 0px; padding: 0px; border-width: 0px" width="336" height="265" frameborder="0" marginwidth="0" marginheight="0" scrolling="no" name="I2"> <![if lt IE 4]> <script src="http://servedbyadbutler.com/adserve/;ID=147917;size=336x265;setID=82436;type=js" type="text/javascript"> </script> <noscript> <a href="http://servedbyadbutler.com/go2/;ID=147917;size=336x265;setID=82436"> <img src="http://servedbyadbutler.com/adserve.ibs/;ID=147917;size=336x265;setID=82436;type=img" border="0" height="265" width="336" alt=""></a> </noscript><![endif]></iframe>   </td> </tr> <tr> <td height="30" valign="bottom" colspan="2"> <p class="header2_black">Related Books</td> </tr> <tr> <td colspan="2" bgcolor="#CC9966" height="2"> <img border="0" src="../images/blank_2x2.gif" width="2" height="2"></td> </tr> <tr> <td bgcolor="#FFFFCC" colspan="2"> <table border="0" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="100%" cellpadding="6" id="table16"> <tr> <td width="100%"> <p class="explanatory_text">For detailed descriptions of asset value models and intensity models, see Bluhm et al (<a target="_blank" href="http://www.riskbook.com/link/bluhm_overbeck_wagner_(2003).htm">2002</a>) and Duffie and Singleton (<a target="_blank" href="http://www.riskbook.com/link/duffie_and_singleton_(2003).htm">2003</a>), respectively.</p> <table border="0" cellpadding="4" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="100%" id="table17"> <tr> <td width="100" align="left" valign="top"><map name="FPMap46"> <area target="_blank" href="http://www.riskbook.com/link/bluhm_overbeck_wagner_(2003).htm" shape="rect" coords="0, 0, 81, 124"> </map> <img border="0" src="../images/book_bluhm_et_al_(2002)_125.gif" usemap="#FPMap46" width="82" height="125"></td> <td align="left" valign="top"> <table border="0" cellpadding="1" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="100%" id="table18"> <tr> <td width="90%" colspan="3"> <p class="title"> <a target="_blank" href="http://www.riskbook.com/link/bluhm_overbeck_wagner_(2003).htm"> <font size="2">An Introduction to</font><br> Credit Risk Modeling</a></td> </tr> <tr> <td colspan="3"> <p class="author"><b>C. Bluhm, L. Overbeck and C. Wagner</b></td> </tr> <tr> <td width="10%"><map name="FPMap47"> <area target="_blank" href="http://www.riskbook.com/main/ratings.htm" shape="rect" coords="0, 0, 89, 15"> </map> <img border="0" src="../images/star_5.gif" usemap="#FPMap47" width="90" height="16"></td> <td width="10%" class="author">quality</td> <td width="70%"> <p class="author"> </td> </tr> <tr> <td width="10%"><map name="FPMap48"> <area target="_top" href="http://www.riskbook.com/main/ratings.htm" shape="rect" coords="0, 0, 89, 15"> </map> <img border="0" src="../images/tech_4.gif" usemap="#FPMap48" width="90" height="16"></td> <td width="10%" class="author">technical</td> <td width="70%">  </td> </tr> <tr> <td width="10%"> <p class="author">2002</td> <td width="10%"> </td> <td width="70%"> <p align="center"><map name="FPMap45"> <area target="_blank" coords="0, 0, 145, 19" shape="rect" href="http://www.riskbook.com/link/bluhm_overbeck_wagner_(2003).htm"> </map> <img border="0" src="../images/pointer_review.gif" usemap="#FPMap45" width="146" height="20"></td> </tr> </table> </td> </tr> </table> <table border="0" cellpadding="4" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="100%" id="table19"> <tr> <td width="90" align="left" valign="top"><map name="FPMap26"> <area target="_blank" href="http://www.riskbook.com/link/duffie_and_singleton_(2003).htm" shape="rect" coords="0, 0, 82, 124"> </map> <img border="0" src="../images/book_duffie_singleton_(2003)_125.gif" usemap="#FPMap26" width="83" height="125"></td> <td align="left" valign="top"> <table border="0" cellpadding="1" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="100%" id="table20"> <tr> <td width="90%" colspan="3"> <p class="title"> <a target="_blank" href="http://www.riskbook.com/link/duffie_and_singleton_(2003).htm">Credit Risk<br> <font size="2">Pricing, Measurement, and Management</font></a></td> </tr> <tr> <td colspan="3"> <p class="author">Darrell Duffie and Ken Singleton</td> </tr> <tr> <td width="10%"><map name="FPMap21"> <area target="_blank" href="http://www.riskbook.com/main/ratings.htm" shape="rect" coords="0, 0, 89, 15"> </map> <img border="0" src="../images/star_5.gif" usemap="#FPMap21" width="90" height="16"></td> <td width="10%"><map name="FPMap22"> <area target="_top" href="http://www.riskbook.com/main/ratings.htm" shape="rect" coords="0, 0, 89, 15"> </map> <img border="0" src="../images/tech_4.gif" usemap="#FPMap22" width="90" height="16"></td> <td width="70%"> <p class="author"> </td> </tr> <tr> <td width="10%"> <p class="author">2003</td> <td width="10%"> </td> <td width="70%"> <p align="center"><map name="FPMap25"> <area target="_blank" coords="0, 0, 145, 19" shape="rect" href="http://www.riskbook.com/link/duffie_and_singleton_(2003).htm"> </map> <img border="0" src="../images/pointer_review.gif" usemap="#FPMap25" width="146" height="20"></td> </tr> </table> </td> </tr> </table> </td> </tr> </table> </td> </tr> <tr> <td bgcolor="#FFFFCC" colspan="2"> <table border="0" cellspacing="0" style="border-collapse: collapse" bordercolor="#111111" width="100%" cellpadding="6" id="table21"> <tr> <td width="100%" bgcolor="#FFFFFF"> <p align="center"><map name="FPMap365"> <area target="_top" href="http://www.riskglossary.com" shape="rect" coords="0, 0, 164, 102"> </map><img border="0" src="../images/logo.jpg" usemap="#FPMap365" width="165" height="103"></p> <p align="center"><span class="verdana10"> <a href="http://www.riskglossary.com/main/disclaimer.htm" target="_self"> Disclaimer</a></span></p> <p align="center">website: <span class="verdana10"> <a target="_top" href="http://www.contingencyanalysis.com"> http://www.contingencyanalysis.com</a></span><br> glossary direct link: <span class="verdana10"> <a target="_top" href="http://www.riskglossary.com"> http://www.riskglossary.com</a></span><br> copyright © Contingency Analysis, 2003</td> </tr> </table> </td> </tr> </table> </td> <td>  </td> </tr> </table> </div> </body>