This year could be the biggest challenge Gulf economies have ever had to face as the low oil price and global economic slowdown land with full force in the region, Moody's Investors Service says. "It is important to bear in mind that the Gulf has never before been financially tested on such a large scale," Moody's said. Gulf companies would have to refinance between US$35 billion (Dh128.5bn) and $40bn this year, as much as $15bn of which is associated with Dubai companies. Although most GCC countries would face credit difficulties this year, the ratings agency said Dubai was "particularly vulnerable due to its closer integration with key sectors of the global economy, particularly real estate, tourism, trade and financial services". tpantin@thenational.ae