First of all, let's understand what the expected return is. Expected return is a mathematical expression of the relationship between various possible future values of assets and corresponding probabilities. So the expected return can be positive (greater than zero) or negative (less than zero). Positive value-indicates that the asset is expected to be profitable; Negative-indicates that the asset is expected to lose money.

Secondly, what is a risky asset? Risk assets are relative to risk-free assets. Treasury bonds are risk-free assets. Because the national debt is guaranteed by national credit, which is also the highest credit among investment products, you basically don't have to worry that the country can't repay your principal. Because national debt is also one of the investment assets, it has expected income, and its expected income is coupon, and the interest of national debt is always greater than zero, and the expected income will be greater than zero (coupon is a fixed income agreed in advance at maturity, so there is no maximum and minimum). Other assets are basically risky assets, including monetary assets (foreign exchange assets), stocks, corporate bonds, gold, futures and so on. There are different degrees of loss risk, so it is expected that the minimum risk will be less than zero.

Finally, foreign exchange assets actually refer to the proportional relationship between the two countries when they exchange currencies. The risks come from the production efficiency, import and export, inflation and the stability of international relations between the two countries.