But in addition to the bonds they are required to hold, banks may, in recessions decide to horde more cash than that, rather than lend it out into a risky economy.
If bonds have a negative yield, then, the theory goes, even in a recession, banks would rather lend the money out than horde it, boosting the level of activity in the economy and so stimulating growth.
Simon Edelsten runs the £296m Mid Wynd investment trust and has been investing in Japan and Eurozone equities for many years. He says bank lending has not increased materially since negative interest rates were introduced.
He says the unprecedented financial circumstances mean that potential borrowers are wary of taking on more debt, so the extra economic activity has not happened.
Gero Jung, chief economist at Mirabaud, based in Switzerland, says his experience of that country is that individuals have not, as policymakers intended, reduced their savings rate and spent more.
He says the very opposite has happened, as people tend to have a savings goal, and if they are earning nothing in interest, they increase the amount of cash they put into savings accounts. This reduces the amount of spending in the economy, and so growth and inflation remain low.
While the supply of money in the economy is a factor of the level of growth, the speed at which the money moves through the economy, what economists call the velocity of money, is the second consideration.
Mr Mac Gorain says inflation would not be something advisers or their clients would have to worry about if negative rates were introduced, as in such an environment, economic growth would be so weak that inflation is a long way off, while the evidence from most of the economies that have negative interest rates is that inflation does not take hold in future.
The negative rate at which governments can borrow money allows politicians to spend more, this increased level of spending may bring the recession to an end sooner.
Peter Toogood, chief investment officer at Embark Group, says that in an economy where government spending is an increasing part of GDP, the returns earned by shareholders tend to be lower, while the policy of very low interest rates mean many companies develop pension fund deficits, because the income paid on the bonds held in those funds falls.
Companies then have to put cash into the pension fund, which is cash that is then not available to spend on expanding the company, or paying higher wages.
Velocity of money
