Pros And Cons Of Rebalancing Stock Market Investments

An asset allocation balances investment risk and return by specifying a particular mix of investments based on the investor’s risk tolerance. For example, an investor might decide to invest 60% of their portfolio in stocks, 30% in bonds and 10% in cash. Investment risk tends to increase as the return on investment increases. Investors can manage the risk of their investment portfolio by combining high-risk investments with low-risk investments.

As the investments change in value, however, the mix of investments may drift away from the original asset allocation. This creates a need to rebalance the investment portfolio by selling some investments and buying others. Otherwise, the growth in value of riskier investments might yield more risk than the investor is willing to tolerate.

But, is rebalancing a portfolio really necessary? What are the pros and cons of rebalancing?

Advantages of Rebalancing

Part of the purpose of an asset allocation is to dilute the impact of each asset class by limiting both the upside and downside impact of the investments. But, when a particular investment grows in value faster than the other investments, you are exposed to more risk than you originally intended. Rebalancing your portfolio returns your investments to your original risk tolerance and reduces the risk that your portfolio will drop in value.

Rebalancing a portfolio also improves diversification. When one stock grows significantly in value, the portfolio becomes weighted more heavily toward that stock, magnifying the impact of that stock on overall portfolio performance.

For example, suppose you invested $10,000 in Tesla
, Inc. (TSLA) on April 1, 2020, when it was about $100 a share, and $10,000 in Intel Corporation
(INTC) when it was about $50 a share. (Figures are rounded to simplify this example.) You would own 100 shares of TSLA and 200 shares of INTC. On April 1, 2021, TSLA reached about $688 a share and INTC reached about $65 a share. Your TSLA shares would be worth $68,800 and your INTC shares would be worth $13,000. Your investment in TSLA would have grown from half of your portfolio to more than 80% of your portfolio.

Rebalancing also avoids the potential for emotions to interfere with your buy and sell decisions. It is hard to follow the advice to buy low and sell high when it means selling winners to buy losers. There can also be some resistance to selling a stock with a lot of gains in a taxable account. (This is why rebalancing is easier in retirement plan accounts, where the investor doesn’t have to pay taxes on capital gains.)

Rebalancing is also a natural consequence of investment glide paths that change the asset allocation over time, such as target date funds. These investment glide paths reduce the risk mix of a portfolio as…