LONDON (BLOOMBERG) - Singapore landlords are paying the penalty for a slowing economy. Alone among the world's major cities, the cost of renting an office with panoramic views is falling as supply outstrips demand.

Annual rents on the upper floors of Singapore's skyscrapers fell 7 per cent to about US$775 (S$1,055) a square meter in the first six months, according to a 23-city index compiled by Knight Frank.

The biggest increase was in Shanghai, where rents climbed 7.6 per cent to US$774. In Hong Kong, the most expensive market, rents rose by 5.9 per cent to US$2,996 a square metre, the broker said.

"There's a classic imbalance in the Singapore market," said Mr Will Beardmore-Gray, head of Knight Frank's tenant representation and agency business. "They had relatively high supply and this has been exacerbated by a poor-performing economy and over development."

Vacancy rates in Singapore were 9 per cent in the second quarter, compared with 3.3 per cent in Shanghai, Knight Frank data show.

Demand for Shanghai office space has been lifted by the technology and creative industries, Mr Beardmore-Gray said. The city has created 300,000 jobs in those sectors since 2009 and is expected to add 100,000 more by 2020, he said.

Manhattan skyscraper rents increased 1.9 per cent to US$1,701 per square metre during the first half, the second-highest in the index, while those in Tokyo and the City of London district were unchanged at US$1,610 and US$1,226 respectively.