Mainland Chinese brokerages and asset management firms are underpinning Hong Kong office rents as the city cements its financial market ties to the world's second-largest economy. Prime office space leased by financial companies from mainland China was 148,000 sq ft last year, a 51 per cent jump from 2013, according to data from realtor CBRE Group. Industrial Securities and Sino Life Insurance were among those that had rented new offices in Hong Kong's central business district in the past two quarters, CBRE said. "Chinese financial services companies are eager to expand here because they see Hong Kong as a perfect springboard for their internationalisation," said Ricky Lau, the head of office leasing at Savills. "Hong Kong's stock market is robust and active. That also attracts Chinese brokerages." Overall rents this year are expected to rise 5 per cent, compared with 0.2 per cent growth last year and a 1.6 per cent decline in 2013, according to CBRE. "A lot of mainland Chinese banks and brokerages still don't have branches in Hong Kong, or they only make up a small portion of the business," said Marcos Chan, CBRE's head of Hong Kong research. Mainland Chinese firms looking to establish Hong Kong offices were willing to pay a premium of 5 per cent for a good location, said Lau, and they were opting for smaller spaces. They were mostly seeking new offices under 10,000 sqft as vacancy rates in prime Central buildings remained low, said JLL. They accounted for 28 per cent of all new lettings in Central last year, it said. Everbright Securities expanded its offices at Far East Finance Centre in Admiralty, paying as much as HK$80 per square foot, a source said. Average rents in Admiralty and Far East Finance Centre are HK$50 to HK$60 per square foot. The average monthly rent in Central was HK$99.30 per square foot in the fourth quarter, compared with HK$59.90 in Wan Chai and HK$45.60 in Hong Kong's east, according to CBRE. New supply this year was expected to be almost two million sq ft, short of the average annual demand of 2.4 million sq ft, said Paul Yien, the regional director of markets at JLL. "Now we're seeing the mainland Chinese firms coming in, starting small. If business is good, they'll double the space," said Craig Shute, CBRE's senior managing director for Hong Kong, Macau and Taiwan. "Hong Kong is still the gateway for China as well as capital going from east to west."