8 Reasons Why You Should Not Trade

Updated on August 10th, 2021

Every physician investor has at one time or another considered trying their hand at trading. Maybe their friends work on Wall Street, or they watch CNBC’s Fast Money, or they were inspired by Dr. Michael Burry on the Big Short. And of course, its hard to go to a cocktail party and not hear about someone making a hugely profitable trade. But take it from a former Wall Street trader that doctors shouldn’t trade. Here’s why:

1. No Trading Edge Compared to Professionals

There is big money being thrown around on Wall Street, which means there are some very smart people working on Wall Street trying to make money. Doctors are smart, but we can’t compete against these equally highly educated hedge fund managers who have an army of research analysts giving them an edge in fundamental analysis, the fastest computers to give them a technical edge in trade execution, and the years of experience of living and breathing the markets 24/7.

2. Differential Between Short and Long-Term Trading Tax Implications

The IRS encourages long-term investing and discourages short-term trading by taxing short-term and long-term capital gains at different rates. Short-term trading profits are taxed as ordinary income, which for physicians can be as high as 39.6%. Long-term capital gains (defined as investments held for longer than 1 year) are taxed at a lower rate (15-20%). This 20% difference in tax rates makes it even harder for traders to beat long-term investors. If you make 8% in your index fund portfolio, you would need to make at least 10% in your trading portfolio to make the same after-tax return if you are in the highest tax bracket.

This disadvantage can be mitigated by trading in your retirement account, but it is counterintuitive to be trying to make short-term money for an account that you can’t withdraw from without penalty until retirement age, which could be 20-30 years in the future.

3. Chance of taking way too much risk

Traders must be disciplined, and be meticulous in their risk management skills. Trading websites often cite risk management as the most important skill of trading. Poor risk management, they say, can ruin even profitable traders. Doctors trying their hand out in trading may not fully appreciate the importance of risk management, and just throw 5%, 10%, or even 20% of their portfolio on a single stock.

In addition, there is always a risk that short-term “trading” eventually just becomes gambling, with the goal simply of getting the rush of a winning trade. As such, there is a danger, especially for a losing trader, that larger and larger portions of a portfolio are allocated to trading in order to make back money lost or to have some winning trades. It is better just to never start.

4. Bid-Ask Spread and Trading Commissions

It costs money to play in the stock market. Brokerage houses make money by charging a commission for each trade you make. For stocks, Fidelity charges $7.95 per trade, and Vanguard charges up to $7.95 per trade, depending on the size of your portfolio. A short-term trader who trades just once per day (250 trades a year) would pay Fidelity approximately $2,000 in commissions yearly. For a physician allocating $100,000 to their trading account, this is already 2% of their portfolio.

This doesn’t even include the bid-ask spread, which is how investment banks and market makers (or mostly their computers) make money off of traders. Market makers will offer retail traders a price they are willing to buy a stock at (the bid) and a price they are willing to sell a stock at (the ask). For example, they might be willing to buy a stock for $10.00 and sell it for $10.05. The difference between the bid price and the ask price is the bid-ask spread (in this case $0.05) and is the profit the market makers earn to create a liquid market. Bid-ask spreads are smaller for more popular, higher-volume stocks, and lower for less popular, lower-volume stocks. A typically bid-ask spread for a high-volume stock might be $0.01 for a $100.00 stock, or 0.01%. Again, if you trade in and out of this stock 50 times (100 trades), losses from the bid-ask spread alone approaches 0.5%, which would be unacceptably high if this were a management fee.

By investing in index mutual funds, there is no trading commission and no big-ask spread. If you prefer ETFs over mutual funds, many index ETFs are commission-free with Fidelity and Vanguard, and the trading volume of these ETFs make the bid-ask spread minuscule. Also, you are trading much less often.

5. Time Commitment Required to Succeed

It takes time to trade well. Remember, you are competing against professionals who have been studying the markets full-time for years, with research analysts to back them up. It’s unlikely that you would be able to beat the market in your spare time. You aren’t going to beat the market during your lunch break, or even by doing 1 hour of homework per stock a week, as Jim Cramer recommends. Dr. Michael Burry from the Big Short attributes his success to poring over financial statements during quiet hours on call. Eventually it became an obsession for him, and he no longer works as a neurologist in order to focus on his hedge fund. Success in trading requires a commitment far beyond what a full-time physician can give.

6. Rarely Beat the Market

Many traders make money in the short-run. Probability states as much. If you flip a coin, with half of investors betting on heads, and half betting on tails, 50% of investors will be making money. These 50% will brag to their friends about their winning trade, or post on message boards touting their investment returns. This is dangerous, because it can lure traders into thinking that they are beating the market, when in actuality, luck has been on their side. In the long-run, very few traders will be able to consistently make money, especially taking into account the structural disadvantages of the bid-ask spread, trading commissions, and unfavorable tax treatment of short-term capital gains.

7. Take Uncompensated Risk

Trading by definition will lead you to hold an undiversified portfolio. This means that you will be taking outsize risk for the same expected gains. Diversification is one of the only free lunches in investing, and by trading you are not taking that free benefit. The expected return of the average individual stock does not exceed the market (otherwise everyone would pile into the highest return stocks), but the standard deviation of returns of an individual stock far exceeds that of the market.

8. Stress of Losing Money

Trading is stressful. Even if you make money, it is stressful. The daily gyrations of the market cannot be controlled, and if your money is at risk, it is stressful. I would argue that trading can be more stressful than most physician jobs (exceptions would probably be emergency medicine or surgery). Being a doctor is stressful enough; there is no reason to allow investing to add any more stress to our lives.

Hopefully, I’ve been able to convince you that trading is a losing proposition. Have you ever traded stocks and had success? Do you have any additional reasons why you shouldn’t trade? Comment below!


  1. Great Post! I came here from WCI. When I was in residency I used to trade a lot, individual stocks, and later with options. Specially with options the rush of trading was addicting. Usually small amounts. I have been an index adept since reading multiple books. Looking backwards, if I would have put all that money into index funds my returns would have been much better than what they were (ok, if you have to ask -100% 4 out of 5 years). I do not regret it. First, I had the opportunity of knowing first hand what it is like to trade, and I enjoyed it. Second, no major damage was done as the sums invested were very small compared to the sums that are invested now. So I would add reason No 9. Personal experience.

    • Thanks for sharing your story, JC. The allure of trading is so strong that I expect most investors to try it at least once. Sounds like you were able to get your investing “education” fairly cheaply and now you’re doing well for yourself.

  2. I enjoy your work, but I’m disheartened by this article. I consider myself a successful physician and trader. Every point listed above resembles the scare tactics used by the entire financial industry to discourage the individual investor.

    I believe financial analysts don’t know any more than the rest of us. Their ‘research’ only serves to promote the firm’s holdings and protect them when things go south. I’m sure Bill Ackman’s fund, Pershing Square, thoroughly researched Valeant before losing billions.

    Commissions are the cost of doing business. There are plenty of low commission brokers who make trading affordable. These costs are dwarfed by the commissions and fees charged by financial advisors and their mutual funds.

    I agree that ETFs and stocks with tight bid/ask spreads are the way to go for the active investor. However, diversification is not always the ‘free lunch’ you describe. While investing in tech, financial, emerging markets, etc sounds great on paper, all of these asset classes become more highly correlated during market downturns.

    My preferred method of trading involves options. There are specific strategies designed to make money in any type of market condition, not just bull markets. It is not without risk and it does take time to learn. I am a firm believer in the ‘tastytrade’ way.

    I spend my water cooler time encouraging medical colleagues to actively invest for themselves.


    • Thank you for your comment. In my opinion, most of the financial industry encourages investors to trade, not to invest in low-cost index funds. CNBC doesn’t run a daily one-hour show about index fund investing. No, they have Fast Money and Options Action, where traders talk about trading stocks and options.

      I’m a big proponent of do-it-yourself investing; much of the blog discusses just that. Doctors should not be paying a financial advisor 1% to invest their money.

      Sectors within an asset class do become more correlated during hard times, but those investors who diversified across asset classes (i.e. stocks and bonds) had fewer losses during the financial crisis (e.g. the 10yr Treasury bond went up 20% in 2008 when the S&P 500 fell 38%).

      I understand the allure of stock options. It allows you to make bets on stocks going up, down, or sideways. You can bet on volatility with options. But ultimately, it just shifts the profit/loss curve around, without changing your expected return (if anything, your expected return goes down because of a higher bid-ask spread).

      I used to love trading also, which is why I wrote my “If You Must Trade, Follow These Five Rules” post.

      Good luck with your trading. I had stumbled upon your blog a few months back, happy to see you’re still writing.


    • I agree with you. I used to be a stockbroker. All that is required is a 4-6 week crash course in finance and passing the Series 7 & 63. I went to college but many brokers and traders are not formally educated. I know traders at Cantor Fitzgerald and brokers at Smith Barney that are high school drop outs. They read the WSJ and watch international news and that’s about it as far as what they know.

  3. For the most part, I leave the trading to the professionals. Honestly, I’ve got better things to do with my time than trying to find the best stocks or time the market. It’s just not the most efficient use of time when I can make more money doing my job or putting effort into increasing my income through my career. I keep up enough to know when the professionals are selling me a bad deal but not enough to keep up with it all.

    PS I like to buy and hold anyways – no short term trading. Short term trading is a losing game.

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