What would it take for investors to switch from bonds into equities in the euro zone?

Despite the fact that long-term interest rates are significantly lower than the growth rate, investors have not switch ed from bonds into equities in the euro zone. This can be explained by the sharp rise in the equity risk premium in the euro zone, that is by a rise in the risk perception of equity investors (which is not visible for example in the case of real estate investors). What would it take for the very low interest rates to trigger a big wave of investment in equities in the euro zone? Risk perception would have to subside: Some causes of the high risk perception (Trump’s tariffs, Brexit, China’s growth slowdown, etc.) are out of the euro zone’s control; But institutional progress could be made in the euro zone (European investment fund, progress with capital flows, fiscal policy coordination), which would reduce risk perception in the zone.