SHANGHAI: The credit crunch has posed a far more serious threat to China's business hub Shanghai than many have expected, as over one quarter of Grade A offices in Lujiazui Finance & Trade Zone were empty at the end of 2008, sources said.

"The Grade A office market in Shanghai was riding a roller coaster throughout 2008. Vacancy rate soared from below 5 percent at the beginning of the year to 15.4 percent by the end of the year," said Albert Lau, managing director with Savills Property Services, Shanghai.

Office market readings diverged across the Huangpu River in 2008, as the average vacancy rate in Pudong reached 25.6 percent in 2008 while that in Puxi stood at 8 percent, Lau said.