Yahoo’s Alibaba Spinoff Lays Bare Weakness in Remaining Business

By spinning off its stake in Alibaba Group Holding Ltd., Yahoo! Inc. will remove a key reason for investors to hold the stock -- increasing pressure on Chief Executive Officer Marissa Mayer to revive growth from other assets.

While shareholders cheered Yahoo’s tax-free plan to distribute its $40 billion holding in the Chinese e-commerce company as a separate public firm, the Sunnyvale, California-based Web portal issued a revenue forecast that fell short of estimates, underscoring the challenge Mayer faces in reviving sales, which have been stagnant for five years. The company’s market value of $45.4 billion on Tuesday was less than the combined value of the stake in Alibaba and Yahoo’s $8 billion holding in Yahoo Japan Corp.