Using leverage in a bull-market

In a bull market, a lot of people get enticed to use leverage to enhance their portfolio returns. Leverage comes in many forms, loans using existing stock as collateral, top-ups on home loans and using them to buy stocks, punting on stock futures etc. 

“Unquestionably, some people have become very rich through the use of borrowed money. However, that’s also been a way to get very poor. When leverage works, it magnifies your gains. Your spouse thinks you’re clever, and your neighbours get envious.

But leverage is addictive. Once having profited from its wonders, very few people retreat to more conservative practices. And as well learned in third grade – and some relearned in 2008 – any series of positive numbers, however impressive the numbers may be, evaporates when multiplied by a single zero. History tells us that leverage all too often produces zeroes, even when it is employed by very smart people.” - Warren Buffett, Berkshire Annual Report, 2010

In this context, let me recount the story of Rick Guerin - Buffett's contemporary and acknowledged by him as "Superinvestor of Grahamville". Guerin lost significantly and dropped out of the investment landscape after the steep crash of 1974 when he received margin calls because he was highly levered. He had to liquidate some of his best investments including Berkshire Hathaway stock. Today, everyone knows of Buffett and Munger but hardly anyone has heard of Guerin. (In fact, to be honest I was also not aware of Guerin's history before reading about it in one of Mohnish Pabrai's interviews).

As Buffett said in the quote above some people can become rich but in an alternate history (Taleb's definition) of events can become a pauper. So, keep away from leverage.

Model Thinking: Online Course

“The better decision maker has at his/her disposal repertoires of possible actions; checklists of things to think about before he acts; and he has mechanisms in his mind to evoke these, and bring these to his conscious attention when the situations for decision arise.” (Herbert Simon, Nobel Laureate)


I recently came across an online class for Model Thinking.  I have started on it and it is very good. You can sign up for the class at the following website: http://www.modelthinking-class.org/

The class will last for ten weeks ending the last week of April. It will be covering two topics per week. Each topic will consist of a series of lectures with some embedded questions to make sure we are understanding the material as well as required and supplementary readings. Every week, starting in week two there will be a quiz. The quiz questions will vary in difficulty from basic competency questions to more challenging numerical calculations.

As you are probably aware, model thinking is critical to a serious investor's success. Without having the right (and enough number of) models in your head, it is not possible to analyze different businesses.

Need for mental models from Charlie Munger:
What is elementary, worldly wisdom? Well, the first rule is that you can't really know anything if you just remember isolated facts and try and bang 'em back. If the facts don't hang together on a latticework of theory, you don't have them in a usable form. 

You've got to have models in your head. And you've got to array your experience—both vicarious and direct—on this latticework of models. You may have noticed students who just try to remember and pound back what is remembered. Well, they fail in school and in life. You've got to hang experience on a latticework of models in your head.

What are the models? Well, the first rule is that you've got to have multiple models—because if you just have one or two that you're using, the nature of human psychology is such that you'll torture reality so that it fits your models, or at least you'll think it does. You become the equivalent of a chiropractor who, of course, is the great boob in medicine.