> Taxing this decision discourages making it—even if only marginally—and makes capital markets dumber and less efficient.

Or it encourages making longer term investment decisions rather than trading like a jittery cocaine addict (which by no small amount of irony a nonnegligible number of traders are already.)

What you’re suggesting is that markets are more efficient when they’re less liquid. That’s both intuitively and empirically wrong.

Why? We already have regulations such as circuit breakers in our markets because unlike what you are claiming, absolute liquidity is not the god you think it is. There can absolutely be such a thing as over-optimization.

They are likely suggesting that incremental, hypothetical increases in market efficiency appear to come at increasingly steep costs which primarily borne by the rest of society at large.

And the evidence for this is … ?

Front-running is an easy example.

So place a limit order.

Do you also preach everyone to learn self-defense when they propose making mugging illegal?

No, in the best world we do both.

Clicking radio button on a website is not at all comparable to learning self defense.

Also, front running is already illegal.

https://www.investopedia.com/terms/f/frontrunning.asp

> Clicking radio button on a website is not at all comparable to learning self defense.

However, stealing money is still stealing money.

> Also, front running is already illegal.

Great! Which means there are sometimes legitimate reasons to clamp down on "hyper-efficient" but socially negative actors.

Front running is illegal.

Finance is 12% of the entire US economy.

What’s the right %?

Clearly less than 12%.

Well, I’m convinced.

What extra liquidity is there for executing trades every microsecond instead of batching them up for thrice a minute trades?

You can have transaction taxes without penalizing small/micro investors.

It’s criminal how the people who trade stocks for a living get away with paying less taxes as a percentage than their janitors.

The drag on efficient capital allocation doesn’t get better if it only applies to large investors, if anything probably the reverse.

This could be solved in part by eliminating the carried interest loophole

> I own 100 shares of Apple… Tim Cook goes on CNBC and says he’s all in on printers. So I want to sell my Apple shares and buy Microsoft. I’m being a smart investor.

No, you’re being a schmuck.

The market moved on that information well before you saw it on the news, loaded up your web browser, and executed the transaction.

Time and time and time again it has been demonstrated that actively trading is negatively correlated with performance. The more frequent you trade, the statistically worse you do.

Besides being empirically true, it makes intuitive sense. Every time you trade you’re engaging with a counter party on the other side of the transaction. With overwhelming likelihood, that counterparty has disproportionately greater (and timelier) access to information and market analysis than you. So every time you trade, you do so at a steep disadvantage.

Invest in the market. Buy and hold. Sell to finance your retirement. Save the gambling for your Vegas fund, not your life savings.

Sorry a colorful example seems to have gone over your head: A financial transaction tax dulls the market response to new information. The primary purpose of markets is to translate information into prices.

Markets that are less efficient in that task hurt long-term retirement investors and day-traders alike.

I would caution you against assuming disagreement is misunderstanding,

A spring only suspension system responds quickly to a bump in the road. If that’s your only metric, it’s good. But a car without a damper is going to be hella uncomfortable. The shock makes it respond slower - it doesn’t mean it doesn’t respond.

Uuuu, While the analogy is nice, I doubt that taxes are decided upon like an engineer deciding on damping coefficients. An engineer has a specification and tries to hit that spec. I have a hard time believing that’s how taxes are set. I would like carbon taxs/credits to be decided upon that way. But if you look at the real systems it’s obvious they weren’t designed that way. Finally, you are correct that you need to be careful in choosing the metric. I think I would also question the desirability of dampinh, which it seems like the other poster was trying to say. The market being dumber is a slower response in your analogy. They want a sports car, not a rolls.

I wanted a sports car as a teenagers and my parents gave me a minivan. It wasn’t what I wanted but it’s likely the reason I’m alive today.

The point of governance to some extent is dealing with the tension between what competing groups of people say they want and actually need

> Markets that are less efficient in that task hurt long-term retirement investors and day-traders alike.

On some level this is true, but the insane quantities being siphoned out of the economy through the financial system is wildly disproportionate to the increasingly-infinitesimal gains in “price efficiency”.

As a long-term investor in the market as a whole, whether Apple’s true per-share value today is 175.01 and not 175.07 is almost completely irrelevant. Even less so the difference between 175.008913 and 175.008916.

We have long since passed a point where there is sufficient liquidity and sufficient price discovery for the purpose of buy-and-hold investment, and every extra dollar that goes to financial services in the name of more accurately determining prices is just a transfer of money from people who provide value to the economy to a class of leeches who provide nearly nothing.

The money is not siphoned out of the economy (unless it all leaves the US/World). The money made in finance is just as any other money, i.e., it is used to consume, invest, save etc.

Btw., no-one is forced to trade incessantly, either.

The money technically being “in the economy” is cold comfort to the workers whose COL has steadily increased while wages have remained flat.

> The market moved on that information well before you saw it on the news, loaded up your web browser, and executed the transaction.

Sounds like insider trading to me.

So for starters, insider trading exists and while it would be great to live in a world where it doesn’t, we live in this world where it certainly does.

Second, even in a magical world where this doesn’t happen, institutional investors have literal teams of analysts working for them. They have bots responding to news reports and public filings, and the lowest latency possible connections to trading platforms.

You have none of this.

You already are taxed for this decision via capital gains taxes.

Not really. I can make a million trades or one to gain $X and pay the same capital gains tax.

A financial transaction tax makes me much worse off in the former case. It disincentivizes trading volume by raising transaction costs, which have been on a long-term trend downward as markets have adopted technology and brokers have engaged in cutthroat competition. I believe that trend has been positive for markets, investors, and the economy as a whole.

Only within one calendar year. In your original AAPL / MSFT example, you’d need to pay taxes at the end of the year on any gains from your AAPL sale assuming that’s as your only trading activity in the year.