INVESTORS could be seriously undervaluing Foster's beer and wine businesses as the market tries to determine what the two businesses are worth in the wake of the company's plan to demerge the two.Morgan Stanley analyst Martin Yule said the $1.5 billion value put on the brewer's wine business was one of three "market misconceptions" impeding Foster's stock price. "We believe the value of inventory alone is more than that," he said. "We think wine has asset value that approaches $4bn.