The demand for a second rent increase applies to almost 15,000 apartments. It comes from six large private housing companies in Malmö. The housing companies are Heimstaden, Willhem, Trianon, Rosengårds fastigheter, Victoriahem and Kanslihuset.

They justify the extra increase with higher interest rates, price increases for materials, repairs and maintenance, and sharply increased district heating prices.

"We have to act on it," says Robin Wilhelmsson, press contact at Heimstaden, which owns just over a third of the apartments affected.

A violation of 70 years of practice

The claim from the six housing companies in Malmö has caused the other party in the negotiations, the Tenants' Association, to go through the roof.

"This could end up with the Wild West in the rental market," says union manager Erik Elmgren.

He describes the claim as a violation of a practice that has been in place for 70 years in the rental market, which states that the rent level is negotiated once a year.

"We did that this year too. But the ink had barely dried on the agreement and so these companies come out and say they need to raise the rent even more on July 1. We take this very seriously," he says.

Heimstaden claims that an interest rate increase of 1 percentage point will lift costs for the company by 10 percent. They warn that maintenance and servicing could suffer if "general cost developments" cannot be covered.

Not sustainable in the long run

Rent increases of 25-30 percent would be needed to cover the cost increases for housing companies over the past year, according to Tomas Ernhagen, chief economist at the trade association Fastighetsägarna.

But the parties agreed last year to base the negotiations on the average cost increases over the past three years.

"It's around 10 percent," says Ernhagen.

Covering this with rent increases of just over 4 percent on average is not sustainable in the long run, according to Ernhagen.

– The landlord acts as an airbag for the tenant. This is often forgotten in the debate, says Ernhagen.