Davos, Switzerland (CNN Business) Banks are meant to hold cash. But in Switzerland, some rich savers are looking for alternatives.

Swiss private bankers say that clients have asked to withdraw large amounts of cash so they can store it themselves, despite the country's reputation as a secure and reliable place for wealthyinvestors.Some of that money may now be sitting inprivate safes and storage.

The unusual moves follow five years of negative interest rates . The policy, intended to keep the Swiss franc from appreciating too much, requires banks to pay to park money with the Swiss National Bank. In some cases, banks have passed a portion of the extra costs on to their most affluent customers.

Such policies are unpopular with clients who are used to earning interest on their deposits, not paying fees. Now, some are weighing more radical ways to protect their money.

"A lot of people [are] thinking about what they should do, and alternatives to this," said Adriel Jost, head of economics at Wellershoff & Partners, a consultancy based in Zurich.

'It's your money'

Norman Villamin, chief investment officer for private banking at Switzerland's UBP, said a limited number of clients have moved their cash into private storage. Some may have sold their business or a home recently, and "can't deploy the cash all in one go," he explained.

Similar requests have been received by bankers at the Swiss private bank Rahn+Bodmer Co., according to partner Martin Bidermann.

"We tell the client, watch out — it's your money," Bidermann said. Some have still moved ahead, he added.

Banks in Switzerland generally see charging customers to hold their cash as a measure of last resort.

"The bank will discuss with the client, if you do these other things with us that allow us to make some money, we won't charge you," Villamin said. "I do think the banks are going out of their way to try and find a way not to charge the large cash holders."

Bidermann said he was aware of similar discussions with clients.

Still, some banks have been forced to levy charges on their biggest account holders after years of extraordinary monetary policy.

Negative interest rates, launched in Switzerland in 2015, have made it harder for the country's banks to generate profit on loans and mortgages. Payments on excess reserves that need to be stored with the central bank have also caused pain.

Credit Suisse CS UBS UBS announced last year that it would apply a negative 0.75% interest rate to cash balances above 2 million Swiss francs ($2.1 million). This means that if an individual client or business holds 3 million Swiss francs ($3.1 million) with the bank for one year, they would be charged 7,500 Swiss francs ($7,750).also said last year that it would apply a 0.75% fee on cash balances above 2 million francs ($2 million) held in Switzerland.

Both banks declined to comment on whether they'd received requests from high net worth clients to take out cash.

No easy feat

Even if clients do want to withdraw large sums of cash, the logistics aren't easy. First, a customer would need to come up with a storage and insurance plan.

Ludwig Karl, a spokesperson for Swiss Gold Safe, which rents safe deposit boxes in Switzerland and Lichtenstein, said that the company has seen increased interest in cash storage since 2015. But getting large amounts of Swiss francs out of a bank can be difficult, he observed.

Bidermann noted that once a client withdraws a significant amount of cash, they could struggle to deposit it again down the line. "Any bank would have questions" if a client arrived with 800,000 Swiss francs in cash five or 10 years from now, he said.

show that the number of banknotes in circulation has increased steadily since the 2008 financial crisis, which ushered in the era of low, and ultimately negative, rates. A spokesperson for the central bank said that low interest rates, along with the Swiss franc's reputation as a safe haven asset, have played a role. Swiss National Bank President Thomas Jordan has said that demand for cash hasn't spiked since 2015. But data show that the number of banknotes in circulationhas increased steadilysince the 2008 financial crisis, which ushered in the era of low, and ultimately negative, rates.A spokesperson for the central bank said that low interest rates, along with the Swiss franc's reputation as a safe haven asset, have played a role.

Notably, the number of 1,000 Swiss franc notes in use has risen faster than any other denomination.

Roche RHHBF In the topsy-turvy world of negative rates, cash isn't the only asset to benefit. Ashok Sewnarain, CEO of IBV Vaults, which has a facility in Zurich, said that storing gold has been big business for him. Bidermann, meanwhile, said clients have wanted to allocate more money to reliable, dividend-paying Swiss stocks, such as healthcare giant

is growing as investors scramble for security. In September, the Swiss National Bank said it would raise the amount that banks can store without being subject to negative interest rates. Even so, the Swiss Bankers Association, a trade group, issued a Pressure on Europe's central banks to alter courseis growing as investors scramble for security. In September, the Swiss National Bank said it would raise the amount that banks can store without being subject to negative interest rates. Even so, the Swiss Bankers Association, a trade group, issued a report the following month claiming that "negative interest rates no longer fulfill their economic purpose."

The European Central Bank, which has had negative interest rates in place for the 19 countries that use the euro since 2014, has also faced calls to investigate the policy's harmful side effects. Banks in Europe and the region's pension funds have suffered as well.

President Christine Lagarde is expected on Thursday to announce the start of a review of the central bank's strategy , including the tools it's used to juice the economy in the past decade.

Before taking the reins in November, Lagarde said that European citizens would be "worse off" without negative interest rates, but promised to monitor their "adverse side effects" as ECB president.