{"id":567,"date":"2007-12-19T15:54:02","date_gmt":"2007-12-19T15:54:02","guid":{"rendered":"http:\/\/scientopia.org\/blogs\/goodmath\/2007\/12\/19\/responding-to-a-faq-what-is-tranching\/"},"modified":"2007-12-19T15:54:02","modified_gmt":"2007-12-19T15:54:02","slug":"responding-to-a-faq-what-is-tranching","status":"publish","type":"post","link":"http:\/\/www.goodmath.org\/blog\/2007\/12\/19\/responding-to-a-faq-what-is-tranching\/","title":{"rendered":"Responding to a FAQ: What is Tranching?"},"content":{"rendered":"<p> I&#8217;ve received an amazing number of requests in the short period of time since my last post to<br \/>\nexplain &#8220;Tranching&#8221;. I mentioned it off-handedly, but a lot of people have heard about its role in the<br \/>\nwhole sub-prime mess, and wanted to know just what it means. I don&#8217;t particularly like writing<br \/>\nabout economics; it&#8217;s just not my bag. But enough people are asking that I feel like I need to answer the question. But this is it folks &#8211; no more of this nonsense after today! There are plenty of other people writing about this, who know more about it, and who are more interested in it, than I am.<\/p>\n<p> It&#8217;s also a relatively simple idea. You&#8217;ve got a bundle made up of, say, 100 loans. You want<br \/>\nto sell at least part of that bundle as a super-safe rated investment. But because it&#8217;s formed from<br \/>\nrisky loans, you know that at least <em>some<\/em> of them are likely to default.<\/p>\n<p> So what you do is divide it into tiers called tranches. Suppose you&#8217;ve got 5 tiers &#8211; levels 1<br \/>\nthrough 5, where 5 is the top tier, and five is the lowest. Each tier covers a part of the bundle. So you might sell 20% of each tier. When the loans are repaid, the way that it works is that tier 1 is repaid first. When tier 1 is fully repaid, then you start paying tier 2, and so on. You can think of it like an overflowing cascade: repayments go to tier one; when it&#8217;s full, the overflow goes to tier 2; when that&#8217;s full, the overflow goes to tier 3, and so on. So if anyone doesn&#8217;t repay the money,<br \/>\nthe people holding the lowest tier, T5, lose <em>everything<\/em> before T4 loses <em>anything<\/em>, and so on up the stack.<\/p>\n<p> Let&#8217;s look at an example. Suppose you sell $100 million worth of loans. You divide it into<br \/>\n5 tranches. So you sell $200,000 of the value of the loans as tier 1, $200,000 as tier 2, etc.<\/p>\n<ol>\n<li> During the first year of the loans, $100,000 is expected to be repaid, and $100,000 is<br \/>\nrepaid. Each tier gets $20,000.<\/li>\n<li> During the second year, $100,000 is expected to be repaid, but repayment falls short. Only<br \/>\n$90,000 is repaid. Tiers one, two, three, and four each get their $20,000; tier 4 takes<br \/>\nthe loss, and only gets $10,000.<\/li>\n<li> During the third year, things get worse &#8211; only $50,000 gets repaid. Tier one and two each<br \/>\nstill get $20,000. Tier three loses half of its expected payment, collecting $10,000. Tiers<br \/>\nthree and four get nothing.<\/li>\n<\/ol>\n<p> Tranching is a good idea. Once again, it&#8217;s a good way of dividing risk. Anyone who invests in risky<br \/>\nloans is taking a chance, but tranching let you divide the chances up, so that people who want safety<br \/>\ncan buy the top tranches, get less of a profit, but know that they&#8217;re not going to get screwed unless<br \/>\nthings really go seriously bad; people who are willing to take their chances in the lower tranches know<br \/>\nthat they&#8217;re taking a significant risk, but they can potentially make a lot more money.<\/p>\n<p> The key, though, is dividing into tranches properly. If, as in the example above, you had five tranches, each taking up 20% of the pie, then the top tranch would be pretty safe: you&#8217;d have to lose 80% of the value of the loans before that tranch lost anything &#8211; and in mortgage loans, even<br \/>\nshitty ones, losing 80% of the value would be quite extraordinary.<\/p>\n<p> But that&#8217;s not how banks set things up. Remember that you&#8217;ve got investors practically begging to<br \/>\nget their grubby little paws onto these high-return, low-risk bonds. But it&#8217;s really <em>only<\/em> the upper tranch that people wanted. The lower tranches &#8211; especially the lowest &#8211; were hard to get rid of. So, what the banks did is, once again, screw around with things.  Some bundles of shit loans were divided into tranches where 80% of the value of the loans were sold as<br \/>\ntip-top ultra-safe investments. That means that if a package of crappy high-risk loans loses 20% through<br \/>\nloan default and foreclosure that the <em>principal<\/em> of the ultra-safe investments are going to be<br \/>\nlost. That&#8217;s not what any sane person considers &#8220;ultra-safe&#8221;. <\/p>\n<p><p> And then, they took the bottom tranches, and re-bundled them. Take the bottom tranch from a hundred different packages of shit loans, bundle it into a new set of bonds, and re-tranch it. Then sell the top 80% of <em>that<\/em> as the top tranch of a bundle. And so on. In many cases, the investors have <em>no clue<\/em> how many levels of re-bundling are going on to create their top-tranch low-risk bond. And you&#8217;ve got all sorts of people who thought they were buying conservative investments who are now stuck with their money invested in bundles of low-tranch shit loans.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>I&#8217;ve received an amazing number of requests in the short period of time since my last post to explain &#8220;Tranching&#8221;. I mentioned it off-handedly, but a lot of people have heard about its role in the whole sub-prime mess, and wanted to know just what it means. I don&#8217;t particularly like writing about economics; it&#8217;s [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[1],"tags":[],"class_list":["post-567","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p4lzZS-99","jetpack_sharing_enabled":true,"jetpack_likes_enabled":true,"_links":{"self":[{"href":"http:\/\/www.goodmath.org\/blog\/wp-json\/wp\/v2\/posts\/567","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.goodmath.org\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.goodmath.org\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.goodmath.org\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.goodmath.org\/blog\/wp-json\/wp\/v2\/comments?post=567"}],"version-history":[{"count":0,"href":"http:\/\/www.goodmath.org\/blog\/wp-json\/wp\/v2\/posts\/567\/revisions"}],"wp:attachment":[{"href":"http:\/\/www.goodmath.org\/blog\/wp-json\/wp\/v2\/media?parent=567"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.goodmath.org\/blog\/wp-json\/wp\/v2\/categories?post=567"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.goodmath.org\/blog\/wp-json\/wp\/v2\/tags?post=567"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}