With investment opportunities sparse amid the country’s weakest economic expansion in a quarter century, Chinese firms reported an 18% jump in cash holdings during their latest quarter, the biggest increase in six years. The $1.2 trillion stockpile – which excludes banks and brokerages – grew at a faster pace than in the U.S., Europe and Japan, according to data compiled by Bloomberg. China Inc.’s unprecedented hoard is frustrating both policy makers and investors. Because companies lack the confidence to spend on new projects, government attempts to boost growth by pumping money into the financial system are falling short. Stockholders, meanwhile, would rather see bigger dividends or share buybacks than a buildup of idle cash on corporate balance sheets.