I’d like to talk today about diversification as a strategy within the theory of portfolio management.
What is portfolio management?
In portfolio management, you have two possible extremes between which most actual portfolios lie– own one thing, or own everything.
The classic example of a person who owns one thing is the owner of a small business, of which the proprietorship makes up his entire personal equity capital in relation to the total investment universe. Most people wouldn’t even consider this person to have a portfolio because he holds nothing else. His business is his portfolio.
Consequently, portfolios imply diversification, and vice versa. The moment you take equity in more than one venture, you have created a portfolio and you are simultaneously diversified. This is the mild hypocrisy of people who warn against diversification (calling it “deworsification”) and counsel investors to maintain a concentrated portfolio. A portfolio may be concentrated to a small number of holdings (let’s say, five or less to pick an arbitrary point of distinction), but this is not a non-diversified portfolio– the very fact that it is a portfolio implies it is diversified.
The standard argument for diversification
Proponents of diversification (or, what we might term “portfolioization” to come up with an even more complicated and hard to speak/spell nomenclature for the phenomenon) argue that diversification is a way to limit risk in equity ownership. It is the “multiple egg baskets” theory, the idea being that if you drop one basket you only lose the eggs inside of the dropped basket, whereas if you carry all your eggs in one basket and drop it, there goes dinner.
But it’s a bit of trickery, because risk can’t be eliminated, only exchanged. In effect, as you diversify (portfolioize), you exchange business risk for market, or economic, risk. The larger your portfolio becomes in terms of total positions, the more it comes to resemble the total universe of equity opportunities in its performance.
With diversification, you are not limiting risk, you are exchanging it. You’re determining how much of your equity will be exposed to each kind of risk in existence, not how much risk you will be exposed to in total (that question is settled by what particular risks you do put into your portfolio).
To summarize, two risk equations:
- business risk vs. market risk
- which business risk?
Standard counter-arguments to diversification (or, why it’s really deworsification)
The case for diversification isn’t complicated and neither is the case against it. There are two main points to consider:
- diversification limits exposure to particular risks, but also limits potential rewards (no free lunch)
- diversification may introduce an altogether separate risk– lack of focus
The first point is fairly self-explanatory. If you only invest X% of your portfolio in a particular risk, you ensure that your maximum loss is never greater than X%, but you also ensure that your maximum gain is never greater than X% * Y, Y being the return of the underlying investment.
So, if you invest 20% of your portfolio in ABC Company and the stock falls by half, thanks to the magic of diversification, you actually only lose 10% of your portfolio (-50% * 20% = -10%). On the other hand, if the stock rises by half, thanks to the magic of diversification you actually only make a return equal to 10% of your portfolio (50% * 20% = 10%).
There’s no free lunch. You only would get to capture the full 50% rise if you had the full 100% of your portfolio exposed. You essentially provide yourself downside insurance because, while your overall gain is capped, your overall loss is capped as well as it can never be higher than the 20% you exposed (provided you aren’t using leverage or shorting).
Perhaps more nefarious, some investment thinkers point out that by diversifying your portfolio, you spread your attention thin and could end up not understanding the individual risks your various positions hold as well as you might if you had one position (or two, or five…) and so, in a quest to limit business risk you actually enhance it because the quality of your analysis falls. Similarly, if you do poor analysis, you might be more prone to rationalize it because, “Oh well, ABC didn’t work out, but I’ve still got bets on DEF and XYZ, I’m sure they’ll turn out okay and make up for the loss– I’m diversified!”
The scarcest thing most investors have is attention they can devote to their investing, not capital.
Is one ever justified in diversifying?
Diversification by itself is not a terrible thing. As discussed above, it really doesn’t confer any advantages beyond the psychological– diversification by itself can’t improve the absolute returns of your portfolio, on net.
It also doesn’t have to be a purposeful strategy. Diversification can happen “by accident” in the following scenarios:
- it would be inappropriate to invest 100% of your capital in a position due to market cap constraints
- you have received new capital inflows following commitment of 100% of your previous capital
- the market moves against you in the middle of taking a position
In the first case, imagine an investment opportunity in a company with a market cap of $100M, in which case the maximum appropriate position one could take without “bidding against oneself” is $5M, but one’s full capital represents the amount of $10M. In this situation, you would only invest half your capital in the idea because investing any more than this might destroy some of the value available. Diversification would be a natural consequence of a situation like this, whether diversification itself was desired or not.
In the second case, imagine you have $10M of total capital in period 0, which you fully invest in X. However, some time later, in period 1, you receive additional inflows of capital of $1M (perhaps you have earned a 10% dividend on your earlier investment in X). Unfortunately, the price of X has risen in the interim and no longer represents the value proposition it once did, although you’re still happy to have your earlier capital invested at the price available in period 0. In this case, you might invest the $1M in opportunity Y and, again, diversification would occur as a natural consequence of these developments whether it itself was desired or not.
In the final case, imagine you have total capital of $10M and have found an investment opportunity which could utilize your entire capital. However, you plan to accumulate in blocks because the investment is not liquid enough to take the $10M at once, and you do not want to make it obvious what you’re doing. You begin by investing $2M. Unfortunately, shortly after you do so a big-mouth blogger lets the whole world know about this great opportunity and the price of the investment opportunity rises to the stratosphere, pricing you out of any meaningful additional accumulation. You’re stuck with 80% of your capital uninvested and must look elsewhere. Again, diversification has occurred as a natural consequence even if it has not been actively sought after.
Ideal portfolio management implies no intended diversification
We’ve seen that diversification can result of two different catalysts– an investor can purposefully seek diversification in order to make a tradeoff between business risk and market risk (to self-insure his own decision-making process by giving up total return potential), or diversification can occur as the natural, unintended consequence of the general investment process.
Ideally speaking, the best situation for any investor to find themselves in is having one idea that has so much return potential relative to risk, that they are so confident about, that they are able to invest 100% of their capital in the idea, thereby avoiding diversification, or portfolioization, entirely. Ideally, one would have all their money at any given time in one idea and only one idea, and when that idea had either fruited, or a more profitable opportunity had arisen elsewhere, the investor would then sell the entire position and look to his next opportunity.
Outside of this ideal, portfolioization may occur inadvertently in pursuit of these very circumstances, in which case there is nothing to be upset over or critical about.
However, if diversification is pursued as a purposeful strategy outside the context of an individual contending with liquidity constraints (ie, perhaps investing 100% of capital in his best idea would put him in a bad position if outside demands for this capital, which are unpredictable, would require him to liquidate at an inopportune time), it stands to reason that an investor might ask himself, or be asked by another, “Why are you investing in something you’re not completely confident about in the first place?”
In other words, perfect confidence is unachievable (although it is the ideal), but it is hard to imagine why an investor would be justified in spreading his bets out across things he was less than as-confident-as-he-could-be about and consoling himself that he was doing well to mind risk thanks to diversification, when he could instead wait for an opportunity where his confidence about the risk-reward picture was as-confident-as-he-could-be and then invest all his capital in that one idea.
And of course, as almost always, I’d be wise to consider and hopefully even heed my own advice!