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Comment by pedrocr | Hacker News Reader

Your active strategies are not against passive traders, they're against other active traders. You can't create one of those differential bets trading only with index funds as they won't take the other side of the unbalanced position you want as they're obliged to follow the index. In your scenarios you'd be winning against some other active investor taking the other side of the bet. Active as a whole can only beat passive as a whole if the market becomes so screwed up there's too much tracking error for passive to work properly. At that point the passive index no longer represents the market average and the active traders can take a larger share of the gains.

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I'm 95% passive, but I think a place where active strategy was observed was with TSLA. actives knew it was on it's way to the index and piled on into it, once it got into index, it got bid up some more and then actives cashed out. passives didn't enjoy the ride up, but suffered the cost of the ride down.

This is what "getting priced-in" looks like. There are strategies around buying shares of companies where their acquisition has been announced, but hasn't closed. Buying is basically a bet that everything goes smoothly.

This is becoming less true as technology has made total market indexes easy and cheap. Instead of buying the S&P 500, I can buy VTI, so TSLA was in my portfolio before and after, to no real effect.

> passives didn't enjoy the ride up

Passive investors who only invest in the S&P 500 didn't enjoy the ride up. But there are plenty of other indexes that people invest in passively that would have held TSLA prior to being added to the S&P 500.

I own SCHB, for example, which tracks the Dow Jones U.S. Broad Stock Market index, and would have owned shares in TSLA long before it was added to the S&P 500.

I think your use of theory and terms is right but you aren't visualizing how it would work in the world where nearly everyone is passive.

Simplest example I cited already: it becomes obvious that company X will default in short order, but it's a member of an index and the market will "buy" it anyway: I can short it (by borrowing from the passives and selling it to them next time they buy the index) and never have to cover since it's bankrupt. That's a simple example of a single-player active skewering the passives.

You can try to figure out what this means in terms of tracking error but it's kinda irrelevant to my point.

In your hypothetical 99.9% passive scenario that doesn't work either because passive funds have long ago disallowed borrowing their stocks to short. If you start with a ~100% passive premise the reality is so different to what a normal market looks like you can't just propose a normal strategy and expect any of it to work.

Hi, I'm not sure I follow this idea that passive investors don't lend their shares. Is that meant to describe the hypothetical world of no active traders, as discussed above, or is it meant to describe the present situation in the investing world today?

In the world as it stands today, passive ETFs and index mutual funds are a huge source of shares to lend. It's one of the ways they can lower the cost of the passive fund (or slightly increase returns above the passive benchmark), as the proceeds from lending shares are returned to investors in the fund. (Not always, but the good ETF operators do this.)

If passive funds made this tradeoff then how would they be influenced by a company going bankrupt? They would just change the tradeoff when that becomes a problem since this is not part of the passive investment strategy.

In the scenario of a company that is obviously not a going concern you can sell stock short to passive investors. The company will then fail and it’s stock will be worth 0. You get to keep the money. I guess the worry would be that the company could raise money by selling shares and use that to avoid becoming insolvent, but at some point a company is going insolvent faster than it can issue new stock.

You can't sell stock short specifically to passive investors. You have to sell it into the market. And since you're trying to sell only that stock and passive investors are buying the whole market your actual net counterparty is a set of some other active traders that hold the mirror position to yours, not the passive traders. The passives will always get the average of the market in that scenario and your above average returns have to come from someone else's below average returns.

I just wrote to you the same thing the parent of your post did. You are missing the part of the scenario where "everyone" except the one player is passive. Both I and the poster broke down the mechanics step by step for you...

You didn't break down anything step by step. If you actually start with an 100% passive market and try having a single active investor in it nothing works. Funds can no longer buy and sell the basket of stocks they need. At that point they'd just trade among themselves and simply not trade with you. To actually be able to trade in the way you describe you'd need a 99.9% passive market where there are still some active traders you are trading with and together you are creating tracking error for the passives siphoning off their gains, which is what I described.

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