What is Stale Price Arbitrage?

For a number of assets, the most recent transaction price at 4PM ET does not fully reflect all available market information. One example is international equities that trade on exchanges that are located in different time zones and close 2-15 hours before U.S. markets. In addition, domestic small-capitization equities and high-yield and convertible bonds often trade infrequently and have wide bid-ask spreads. This can cause the most recent transaction price to be much different from the price that one would see in a liquid market at 4 PM, even for assets that trade on exchanges that are open at that time. Investors can take advantage of mutual funds that calculate their NAVs using stale closing prices by trading based on recent market movements. For example, if the U.S. market has risen since the close of overseas equity markets, investors can expect that overseas markets will open higher the following morning. Investors can buy a fund with a stale-price NAV for less than its current value, and they can likewise sell a fund for more than its current value on a day that the U.S. market has fallen. Similar opportunities exist when the values of infrequently or illiquidly-traded domestic assets have recently changed. Also referred to as Net Asset Value Arbitrage or NAV Arbitrage.