<p>Rebalancing is the periodic adjustment of a portfolio's weights to align with its target <a href="/NewSite/encyclopedia/asset-allocation/" class="ency-link">asset allocation</a>. This process ensures that the portfolio maintains its desired level of risk and return.</p>

<h2>How It Works</h2>
<p>Rebalancing involves selling some assets that have increased in value and buying others that have decreased. This is typically done when the weights of certain assets deviate from their target allocation by a specified percentage, known as a rebalancing threshold. For example, if an investor has a target allocation of 60% stocks and 40% bonds, but the stocks have risen to 70% of the portfolio, the investor might rebalance by selling some stocks and buying more bonds.</p>
<p>There are two common methods of rebalancing: time-based and percentage-based. Time-based rebalancing involves rebalancing at regular intervals, such as once a year. Percentage-based rebalancing involves rebalancing whenever an asset's weight deviates from its target by a certain percentage, such as 5%.</p>

<h2>Why It Matters</h2>
<p>Rebalancing is a crucial aspect of portfolio management for several reasons. Firstly, it helps to maintain the portfolio's risk level. If left unchecked, a portfolio can become increasingly concentrated in a few assets, leading to higher risk. Rebalancing helps to diversify the portfolio and reduce risk.</p>
<p>Secondly, rebalancing can enhance returns. By selling high-performing assets and buying low-performing ones, rebalancing can lock in profits and buy low. For instance, an investor who rebalanced their portfolio in 2000, at the peak of the dot-com bubble, would have avoided much of the subsequent market crash.</p>