An asset allocation strategy in which assets are assigned a fixed percentage in a portfolio and readjusted to their target weights periodically. The readjustment allows the portfolio to remain properly weighted, and forces the sale of outperforming assets and purchase of underperforming assets. In a constant ratio plan, the manager must choose how often to rebalance the portfolio and weigh the tradeoff between the desire to frequently rebalance and the added transaction costs that will result. Taobiz explains Constant Ratio Plan A constant ratio plan differs from buy-and-hold and momentum strategies. Buy-and-hold investors set one allocation and don't rebalance, while momentum investors sell underperforming assets and buy outperforming ones. A constant ratio plan performs best in a volatile market with a general mean-reverting pattern. For example, if the stock market is oscillating, a constant ratio plan will buy when stock prices fall and sell when they rise.