How soon are we going to approach an era of negative rates?

There has already been some report saying NatWest is ready to introduce negative rates. This is entirely possible, especially when there is an increasing degree of global risks. The saving interest rate is determined by the policy rates, the demand for loans, the riskiness of saving, the tolerance to risk and the level of competition in the industry. Currently, most central banks are taking expansionary monetary policies, though the US Fed is considering to raise rates later this year. There are several global events, such as Brexit, creating more risk in the market. Moreover, the market behaviour has changed from an aggressive one to a risk averse one that although the returns of many hedge funds increase last quarter, more funds have been withdrawn from the hedge funds, and the demand for low risk securities have increased, the prices of government bonds, large and secure large cooperate bonds have also increased. Moreover, the level of competition has decreased due to several merges of big banks. Among the facts that could lead to negative rates, the only several facts standing in the way are the safety of the banking industry and the acceptance of the public and the regulators.