I think that the post’s points on markets not being fully efficient are reasonable, but I also think that any reliable strategy will see its value get eaten pretty quickly, unless it relies on something that only a few people know about.
It seems like the author agrees:
All of the approaches I’ve mentioned are likely to outperform by less than history suggests, due to the increased amount of investment attempting to exploit them. That increased investment over the past decade or two doesn’t look large compared to the magnitude of the inefficiencies, but if trading volume on these etf’s becomes comparable to that of leading etf’s, I’d expect the benefits of these etf’s to go to zero.
The 3% number may already be accounting for this trend, but even if it does, this approach comes with (I assume) a bit more risk than a standard index-fund strategy, plus the need to occasionally rebalance one’s portfolio, the fear that comes with sometimes underperforming the market, etc.
And of course, the outside view lets us notice that nearly every person who ever thought they could reliably beat the market was wrong, including many people who were at least as well-informed as the author. That reduces my expectation for the benefits of this strategy. I’d put higher credence on it working that I would for most investor-recommended strategies, since I have a pretty high opinion of the author’s past work, but I wouldn’t go so far as to advocate that any particular EA follow the strategy to the letter (especially since each person has their own financial strategy/goals).
My approach, as someone who doesn’t want to spend a lot of time thinking about small percentage gains/messing around with rebalancing and such, is to just use Betterment (Wealthfront is equally good), an index-fund startup that handles rebalancing and tax benefits for you. I’ve had solid, slightly-above-market returns from them for years, and the interface is really good.
I agree that Bayesian Investor’s strategy has a high chance of not beating the market, has somewhat higher risk, and would probably result in you occasionally rebalancing your portfolio, but it still seems like it’s very much worth using or at least worth having someone look into.
The funds Bayesian Investor suggests you invest in are ETFs, which I think decreases the need for doing much rebalancing. And rebalancing takes little time. All you need to do is buy and sell from a handful of ETFs; I doubt this would take much more than an hour or so. There’s also the transaction cost of buying and selling stocks, but these costs are low, too, and probably under $100 per year.
I understand many people knowledgable about about investing have thought they could beat the market and were wrong, but how many people were both knowledgeable about investing and about rationality but were still wrong? Given how few rationalists there are, I doubt there have been many.
If we assign a 1⁄3 chance of the strategy beating the market by 3% and otherwise matches the market, then with $100,000 in investments the strategy would in expectation increase our earnings by $1,000 per year. I extremely roughly estimate the annual cost of rebalancing to be $100 per year, including lost earnings due to opportunity cost, which results in the strategy giving you a net profit of $900 per year. This sounds like a good deal to me. And with $1,000,000 invested it would net $9,900 per year.
There’s also the potentially increased risk, but for the amounts of money we’re dealing with, I think we should be pretty much risk neutral. This is because individuals who aren’t extremely wealthy generally can only the amount of funding a non-tiny organization gets by a small amount, and when changing the amount of funding by only a small amount diminishing marginal returns to funding would have little effect.
I don’t know much about investing, but a couple of quick comments might be helpful:
I understand many people knowledgable about about investing have thought they could beat the market and were wrong, but how many people were both knowledgeable about investing and about rationality but were still wrong? Given how few rationalists there are, I doubt there have been many.
Is there any empirical reason to think that knowledge about ‘rationality’ is particularly helpful for investing?
If we assign a 1⁄3 chance of the strategy beating the market by 3% and otherwise matches the market
1⁄3 chance seems possibly orders of magnitude too high to me.
Is there any empirical reason to think that knowledge about ‘rationality’ is particularly helpful for investing?
Yes. Rationalists are likely to know about, and adjust for, overconfidence bias, and to avoid the base-rate fallacy. Presumably Bayesian Investor already knows that most people who thought they could beat the market were wrong, and thus took this into account when forming their belief that the strategy can beat the market.
And it’s not necessarily the case that Bayesian Investor’s strategy is worth doing for everyone and that people just don’t do it because they’re stupid. The strategy carries more risk than average strategies, and this alone is possibly a good enough reason for most people to avoid it. Effective altruists, however, should probably be less risk averse and thus the strategy is more likely to be useful for them.
Also, we’ve been saying most people who think they can beat the market are wrong, but on reflection I’m not sure that’s true. My understanding is that using leverage can, in expectation, result in you beat the market, and I suspect this is well know among those knowledgeable about investing. People just avoid doing it because it’s very risky.
I doubt that following my advice would be riskier than the S&P 500 - the low volatility funds reduce the risk in important ways (mainly by moving less in bear markets) that roughly offset the features which increase risk.
It’s rational for most people to ignore my advice, because there’s lots of other (somewhat conflicting) advice out there that sounds equally plausible to most people.
I’ve got lots of evidence about my abilities (I started investing as a hobby in 1980, and it’s been my main source of income for 20 years). But I don’t have an easy way to provide much evidence of my abilities in a single blog post.
What sort of other advice is out there that’s somewhat conflicting but equally plausible? The only one I can think of is that you should basically just stick your money in whatever diversified index funds have the lowest feeds. But even if this advice is just as plausible as your advice, your advice still seems worth taking. This is because if you’re wrong and I follow your strategy anyways, pretty much the only cost I’m bearing is decreasing my returns by only a small amount due to increased management fees. But if you’re right and I don’t follow your strategy, I’d miss out on a much less small amount of returns.
Here are a few examples of strategies that look (or looked) equally plausible, from the usually thoughtful blog of my fellow LessWronger Colby Davis .
This blog post recommends: - emerging markets, which overlaps a fair amount with my advice - put-writing, which sounds reasonable to me, but he managed to pick a bad time to advocate it - preferred stock, which looks appropriate today for more risk-averse investors, but which looked overpriced when I wrote my post.
This post describes one of his failures. Buying XIV was almost a great idea. It was a lot like shorting VXX, and shorting VXX is in fact a good idea for experts who are cautious enough not to short too much (alas, the right amount of caution is harder to know than most people expect). I expect the rewards in this area to go only to those who accept hard-to-evaluate risks.
This post has some strategies that require more frequent trading. I suspect they’re good, but I haven’t given them enough thought to be confident.
I think that the post’s points on markets not being fully efficient are reasonable, but I also think that any reliable strategy will see its value get eaten pretty quickly, unless it relies on something that only a few people know about.
It seems like the author agrees:
The 3% number may already be accounting for this trend, but even if it does, this approach comes with (I assume) a bit more risk than a standard index-fund strategy, plus the need to occasionally rebalance one’s portfolio, the fear that comes with sometimes underperforming the market, etc.
And of course, the outside view lets us notice that nearly every person who ever thought they could reliably beat the market was wrong, including many people who were at least as well-informed as the author. That reduces my expectation for the benefits of this strategy. I’d put higher credence on it working that I would for most investor-recommended strategies, since I have a pretty high opinion of the author’s past work, but I wouldn’t go so far as to advocate that any particular EA follow the strategy to the letter (especially since each person has their own financial strategy/goals).
My approach, as someone who doesn’t want to spend a lot of time thinking about small percentage gains/messing around with rebalancing and such, is to just use Betterment (Wealthfront is equally good), an index-fund startup that handles rebalancing and tax benefits for you. I’ve had solid, slightly-above-market returns from them for years, and the interface is really good.
I agree that Bayesian Investor’s strategy has a high chance of not beating the market, has somewhat higher risk, and would probably result in you occasionally rebalancing your portfolio, but it still seems like it’s very much worth using or at least worth having someone look into.
The funds Bayesian Investor suggests you invest in are ETFs, which I think decreases the need for doing much rebalancing. And rebalancing takes little time. All you need to do is buy and sell from a handful of ETFs; I doubt this would take much more than an hour or so. There’s also the transaction cost of buying and selling stocks, but these costs are low, too, and probably under $100 per year.
I understand many people knowledgable about about investing have thought they could beat the market and were wrong, but how many people were both knowledgeable about investing and about rationality but were still wrong? Given how few rationalists there are, I doubt there have been many.
If we assign a 1⁄3 chance of the strategy beating the market by 3% and otherwise matches the market, then with $100,000 in investments the strategy would in expectation increase our earnings by $1,000 per year. I extremely roughly estimate the annual cost of rebalancing to be $100 per year, including lost earnings due to opportunity cost, which results in the strategy giving you a net profit of $900 per year. This sounds like a good deal to me. And with $1,000,000 invested it would net $9,900 per year.
There’s also the potentially increased risk, but for the amounts of money we’re dealing with, I think we should be pretty much risk neutral. This is because individuals who aren’t extremely wealthy generally can only the amount of funding a non-tiny organization gets by a small amount, and when changing the amount of funding by only a small amount diminishing marginal returns to funding would have little effect.
Am I missing something?
I don’t know much about investing, but a couple of quick comments might be helpful:
Is there any empirical reason to think that knowledge about ‘rationality’ is particularly helpful for investing?
1⁄3 chance seems possibly orders of magnitude too high to me.
Yes. Rationalists are likely to know about, and adjust for, overconfidence bias, and to avoid the base-rate fallacy. Presumably Bayesian Investor already knows that most people who thought they could beat the market were wrong, and thus took this into account when forming their belief that the strategy can beat the market.
And it’s not necessarily the case that Bayesian Investor’s strategy is worth doing for everyone and that people just don’t do it because they’re stupid. The strategy carries more risk than average strategies, and this alone is possibly a good enough reason for most people to avoid it. Effective altruists, however, should probably be less risk averse and thus the strategy is more likely to be useful for them.
Also, we’ve been saying most people who think they can beat the market are wrong, but on reflection I’m not sure that’s true. My understanding is that using leverage can, in expectation, result in you beat the market, and I suspect this is well know among those knowledgeable about investing. People just avoid doing it because it’s very risky.
Hi, I’m Bayesian Investor.
I doubt that following my advice would be riskier than the S&P 500 - the low volatility funds reduce the risk in important ways (mainly by moving less in bear markets) that roughly offset the features which increase risk.
It’s rational for most people to ignore my advice, because there’s lots of other (somewhat conflicting) advice out there that sounds equally plausible to most people.
I’ve got lots of evidence about my abilities (I started investing as a hobby in 1980, and it’s been my main source of income for 20 years). But I don’t have an easy way to provide much evidence of my abilities in a single blog post.
What sort of other advice is out there that’s somewhat conflicting but equally plausible? The only one I can think of is that you should basically just stick your money in whatever diversified index funds have the lowest feeds. But even if this advice is just as plausible as your advice, your advice still seems worth taking. This is because if you’re wrong and I follow your strategy anyways, pretty much the only cost I’m bearing is decreasing my returns by only a small amount due to increased management fees. But if you’re right and I don’t follow your strategy, I’d miss out on a much less small amount of returns.
Here are a few examples of strategies that look (or looked) equally plausible, from the usually thoughtful blog of my fellow LessWronger Colby Davis .
This blog post recommends:
- emerging markets, which overlaps a fair amount with my advice
- put-writing, which sounds reasonable to me, but he managed to pick a bad time to advocate it
- preferred stock, which looks appropriate today for more risk-averse investors, but which looked overpriced when I wrote my post.
This post describes one of his failures. Buying XIV was almost a great idea. It was a lot like shorting VXX, and shorting VXX is in fact a good idea for experts who are cautious enough not to short too much (alas, the right amount of caution is harder to know than most people expect). I expect the rewards in this area to go only to those who accept hard-to-evaluate risks.
This post has some strategies that require more frequent trading. I suspect they’re good, but I haven’t given them enough thought to be confident.