Charging Banks to Keep Their Money at the Central Bank
Negative interest rates invert the normal order, making lenders pay to hold money rather than earning on it. Several central banks tried it, and it works in strange and limited ways.
Turning Interest Upside Down
Interest is normally something a lender earns for parting with money. Negative interest rates reverse this: the lender pays for the privilege of holding money. When a central bank sets a negative rate, banks that hold reserves at the central bank are charged for them rather than paid.
The idea, once purely theoretical, was adopted by several central banks facing weak economies and inflation that was too low. It is a deliberate attempt to push banks to do something with their money rather than hold it, by making holding it costly.
A negative rate is a penalty for holding money still. The hope is that penalising idle reserves pushes banks to lend and investors to spend, though the money has limited places to go.
The Intended Mechanism
The logic runs through the banking system. If a bank is charged for holding reserves at the central bank, it has an incentive to do something more productive with the money, lend it, buy assets, rather than let it sit and incur the charge.
Lower rates throughout the economy should follow, encouraging borrowing and spending, weakening the currency to help exports, and pushing investors out of safe low yielding assets into riskier productive ones. The negative rate is meant to be a stronger version of an ordinary rate cut, applied when rates are already at zero and the economy still needs support.
The Floor That Should Not Be Crossable
Negative rates were long thought impossible because of a simple alternative: cash. If a bank is charged to hold reserves, why not hold physical cash instead, which yields zero, better than negative? The existence of zero yielding cash should put a floor under interest rates at zero.
In practice, holding large amounts of physical cash is costly and impractical, storage, insurance, security, transport, so banks tolerated modestly negative rates rather than switching to cash. This gave central banks a little room below zero, but not much, since deeply negative rates would eventually make cash worth the trouble. The floor is not exactly zero, but it is not far below it, which limits how much easing negative rates can deliver.
| Rate level | Bank response |
|---|---|
| Slightly negative | Tolerate the charge, cash not worth the hassle |
| Deeply negative | Switch to physical cash, defeating the policy |
Why It Half Worked
The evidence on negative rates is mixed. They did push down rates and weaken currencies somewhat, providing some easing. But the transmission to the wider economy was blunted by a specific problem: banks were often reluctant to pass negative rates on to ordinary depositors.
A bank that charges retail customers to hold deposits risks them withdrawing to cash and losing their business. So banks largely absorbed the negative rates on their reserves rather than passing them to depositors, which squeezed bank profitability and blunted the intended effect. The policy worked on wholesale rates and financial markets more than on the retail lending it was meant to stimulate.
The Side Effects
Negative rates had costs that grew with time. They squeezed bank profit margins, since banks earn partly on the gap between lending and deposit rates, which negative rates compress. A weakened banking system is less able to lend, which works against the policy goal.
They also distorted savings and pensions, since savers earned nothing or paid to save, and pension funds and insurers that rely on positive yields struggled to meet their obligations. Prolonged negative rates raised concerns about the health of the financial institutions they depended on, which is why they were generally treated as an emergency measure rather than a normal tool.
The Bottom Line
Negative interest rates make holders of money pay rather than earn, a deliberate attempt to push idle reserves into the economy when rates are already at zero. They work in a limited way, held back by the floor that physical cash provides and by banks reluctance to pass the charge to depositors, which blunts the transmission to real lending. Their side effects, squeezed bank profits and strained savers and pension funds, grow with time, which is why negative rates are an emergency measure with real limits rather than a routine lever.