Portfolio Rebalancing Based on Expected Profit and Trading Costs (Redux)
The idea of rebalancing a portfolio to maintain target asset allocation percentages is simple in theory, but tricky in practice. It is not obvious how far asset class percentages should be away from their targets before it makes sense to rebalance. I have recently improved a scheme that I have now fully automated in my portfolio spreadsheet. Instead of obsessing over my portfolio’s returns, a script emails me when I need to rebalance. Investors should use any new savings or withdrawals they make as opportunities to rebalance by buying low asset classes or selling high ones. However, as a portfolio grows, rebalancing with new savings and withdrawals is unlikely to be enough to maintain balance when asset classes have big swings. Common advice is to rebalance a portfolio on a fixed schedule, such as yearly. This has the advantage of allowing investors to avoid obsessing over their portfolios all the time, but has the disadvantage of missing potentially profitable opportunities to reb...