Online course of the day, investing department

November 21, 2012

Would you like to take a free online university course which teaches you the basics of quantitative analysis and also helps you manage your money so that you get high returns with low risk? Of course you would. Let me introduce you to Computational Investing, Part I, taught by Tucker Balch, Ph.D., on the Coursera website.

Under “Recommended Background” we’re told that “the primary prerequisite is an excitement about the stock market”. And there are two recommendations under “Suggested Readings”, including All About Hedge Funds : The Easy Way to Get Started, by Robert Jaeger. (Apparently it “explains how any investor can take advantage of the high-potential returns of hedge funds while incorporating safeguards to limit their volatility and risk”.)

This is a genuine university course: it’s the same one that Balch teaches at Georgia Tech. And so you’d expect a few disclaimers, at least, along the lines of “this is an introductory course, it’ll help you understand a few concepts, and maybe be the first step on the road to becoming a quantitative analyst yourself one day, but please, kids, don’t try this at home”.

You might expect such a thing, but you’d be disappointed. Instead, you get the exact opposite. Check out Week 4 (you might have to register; it’s easy and free) and then “Lecture Video 1.2: Response to Questions from Students”. According to Balch, the “number one most popular question” he gets asked is “Do I use these techniques to manage my own funds?”. He responds as forthrightly as he can:

The answer is yes.

Balch continues:

I have a number of different investments that I use these approaches for. With regard to my company, Lucena Research, we manage a few small funds as a way to test our techniques and validate them. One of them in particular I’ll show you in just a moment.

It’s far from clear how a student who has merely taken an online course might ever hope to replicate the returns that Balch manages to generate at Lucena (“Hedge Fund Technology for the Strategic Investor”). But in any case Balch does share with us a Lucena portfolio which “was developed specifically to be low risk”. It looks like this:

I look at this and I immediately get suspicious: there’s something quite Madoff-like about the way in which Balch’s returns go steadily up and to the right regardless of what the stock market is doing. Here’s how Balch explains what’s going on in there:

This approach was developed specifically to be low risk. It includes a basket of less than 20 equities that are traded about every 2 weeks. It’s 2X leveraged, meaning that half of the money is borrowed investment.

So this approach is a 2X levered fund with less than 20 stocks? Sounds very risky to me. But Balch shows us the numbers to prove that it isn’t:

The first thing to note here is that although Balch told us he was going to show us one of the “small funds” that he uses “to test our techniques and validate them”, this does not look like a real-money fund. There’s no indication, for starters, of what the borrowing costs are: if the fund is indeed 2X leveraged, how much does it cost to borrow $10 million on an ongoing basis?

Maybe those numbers are somehow incorporated into the returns — but then there’s the very odd section on “Transaction Costs”. The commissions bit makes sense: if you trade 10 times a week on average for 20 months, then that’s about 860 trades in all, and the commissions add up to about $20 per trade.

But then there’s the “slippage”, which doesn’t make sense. Commissions are real costs: they’re the amount of money you have to pay your broker to execute your trades. Slippage, on the other hand, is not a real cost, but rather a theoretical cost: it’s the difference between the official market price of a security, and the price you actually end up paying. It’s a way of taking a theoretical portfolio, which always trades at the market price, and adjusting the returns to make them more realistic. If you have a real portfolio, as Balch suggests that he does, then there’s no “slippage”: the slippage is built in to your actual returns.

So it seems that Balch, after promising to show us the returns that one of his “small funds” has generated, ends up doing no such thing. (And also, I don’t think that a $20 million fund would count as “small” for a college professor who tells us that most of his money is in his TIAA-CREF retirement account.) Still, he says:

This is a conservative approach which nets about 15%-20% per year. You can absolutely follow more risky approaches that’ll provide higher returns. This is the kind of approach I follow.

In other words, if you take what Balch is saying at face value, he’s managed to come up with a conservative investment strategy, which is levered 2-to-1, which generates returns of more than 15% per year, which he follows himself. And he encourages his students to try to do the exact same thing.

There are lots of courses on Coursera, and most of them aren’t as sketchy as this. But I do think that what we’re seeing here is the beginning of a serious problem with online universities like Coursera: you can never be sure about their quality control. And in general, if you’re taking a college course where the professor encourages you to lever up a small number of stock-market investments in the hope of getting low-volatility 20% returns, I’d advise thinking twice about that professor, and that course. Because it just doesn’t pass the smell test.


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