The study, conducted by Felix Mindl and Dr Oliver Arentz, investigated the impact of short-term rentals on the Cologne housing market, with findings that come as a stark warning to other urban areas.

The research found that pressure on the housing market has been steadily increasing over the past 10 years, with the number of short-term rental accommodations in Cologne increasing from 500 to nearly 6,200 in the last five years alone.

Of these accommodations, 41% are rated as professional of which 65% are owned by hosts with multiple accommodations.

The average income from short-term rentals exceeds that of long-term rentals after only 90 booked days.

“While a large proportion of hosts can be considered home sharers, we find an increasing proportion of providers who have developed a professional business model from short-term rentals. Professional short-term rentals are available to tourists throughout the year and thus compete directly with long-term tenants, for whom the rooms are then no longer available,” said Felix Mindl.

The research also found that 14.2% of overall rent increases within the study period can be attributed to short-term rentals – this results in a rent increase of around 320 Euros per year for new tenants.

The authors suggest that a registration process for the hosts could make an important contribution to improving transparency of the market structure.