What it means
Interest rates were supposed to stop at zero, and negative interest rate policy breaks that floor: the central bank charges banks for parking money, turning the safest asset into one that slowly leaks. The logic is a nudge down the risk ladder, since if reserves cost money banks would rather lend, and if deposits near zero yield nothing, households and firms would rather spend or invest.
The European Central Bank went negative in 2014, cutting the deposit facility rate below zero to fight weak inflation, and its explainer pages describe the policy as charging banks that leave excess funds with the central bank. Denmark, Switzerland, Sweden and Japan ran versions too, taxing reserves to defend a currency level or to fight deflation, which made the policy a mainstream tool of the 2010s rather than a curiosity.
The side effects concentrate in banking. Lending margins compress when loan rates fall faster than deposit rates can follow, since banks fear charging retail customers for deposits, and profitability suffers.
Public acceptance proved the quiet constraint too, because savers tolerated zero but resented charges, which is one reason retail deposits rarely went negative even at the policy's depths. Cash sets the practical floor.
People can always convert deposits to banknotes at 0%, so deeply negative rates are self-limiting unless cash itself is restricted, which no major central bank has attempted. Researchers tracked bank lending, money-market rates and exchange rates through the experiment, finding that transmission worked but dimmed as rates went deeper below zero.
The era has mostly closed. The ECB returned to positive rates in 2022 and the Bank of Japan ended its negative policy in 2024, leaving NIRP as a documented experiment with measured results.
For a business owner, the lesson from the experiment is about regime change: when deposit money costs banks to hold, loan pricing, cash management and even invoice terms all shift in ways worth watching. For treasurers, the legacy is a playbook that documents which products turn negative first, how banks pass the cost through, and which contracts never contemplated a minus sign.
In practice
Real-world examples.
Example
A bank introduces charges on corporate deposits above a threshold, passing through the central bank's negative deposit rate to its largest clients. Smaller balances stay free, so the cost lands on the firms with the most idle cash. Treasurers respond by spreading balances or investing the excess.
Example
A mortgage lender in a negative-rate country issues home loans at rates near zero, and savers see money market funds waive fees to stay positive. The regime inverts old instincts about idle balances. Holding cash becomes a cost rather than a comfort.
Example
A pension fund moves from short government paper into longer maturities as negative yields make holding bills a guaranteed small loss. The extra yield comes with more price risk if rates rise. The fund's investment committee documents the trade-off before approving the shift.
Formula
Calculation
Cost of idle reserves = reserves x negative rate. A bank parking $10 billion at minus 0.5% pays $10,000,000,000 x 0.005 = $50 million a year, which is precisely the incentive the policy creates to lend instead.
The same arithmetic reaches corporate customers when a bank passes the charge on. A company holding $20 million of surplus deposits at a charge of 0.2% pays $20,000,000 x 0.002 = $40,000 a year, so moving $10 million of that cash into short-dated securities that yield 0% would halve the bill to $20,000.Case study
Seen in the real world.
In this illustrative fictional case, Margarethe, treasurer of a Danish exporter, watches her bank introduce fees on large corporate deposits as negative rates bite. She shortens the company's cash cycle, pays suppliers on normal terms instead of early, and moves surplus into a laddered bond programme. Her finance committee treats the fee notices as a signal that the rate regime, not the bank, changed. Her team calculates that leaving $20 million in current accounts at a 0.2% charge would cost $40,000 a year, which is more than the cost of running the bond programme. When the regime later ends, the same ladder rolls into positive-yielding paper without any disruption to payments.
Watch out
Common mistakes.
- Believing negative rates mean banks pay you to borrow, when borrowers still pay interest, just less, and the negative rate applies mainly to bank reserves at the central bank. Retail terms differ by bank and contract.
- Ignoring the margin squeeze on lenders, when the policy compresses the spread between loan and deposit rates, and bank profitability is the channel through which the medicine can sicken.
- Assuming the policy is permanent, when the ECB and Bank of Japan both exited, and negative rates proved a cycle tool rather than a new normal.
Questions
People also ask.
What is a negative interest rate policy?
A central bank setting its policy rate below zero, so commercial banks pay to hold reserves. The charge is meant to push banks toward lending and economies toward spending. Rates below zero invert the normal deposit relationship.
Which central banks used it?
The European Central Bank from 2014, plus Denmark, Switzerland, Sweden and Japan. Most exited by the mid-2020s, with the Bank of Japan the last to leave in 2024. The ECB's explainer pages document the 2014 move.
Did negative rates work?
Studies credit them with easing conditions without the feared cash hoarding, but bank profitability suffered and benefits were modest. Most central banks treat the tool as available but reserved. Exit costs proved manageable when inflation returned.
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