SAN FRANCISCO – Internet pioneer Yahoo, under pressure from unhappy shareholders and desperate to avoid a huge investment-related tax bill, will break itself apart – just not in the way it had previously planned.

The company will now aim to spin off its struggling Internet business – essentially, everything associated with the Yahoo brand name – into a new company. Yahoo itself would then become little more than a holding company for its $32 billion stake in Chinese e-commerce giant Alibaba.

For most of the past year, Yahoo had planned instead to spin off the Alibaba stake into a separate holding company called Aabaco. That corporate maneuver was designed to sidestep more than $10 billion in taxes Yahoo might otherwise owe. But the IRS jeopardized that plan by refusing to guarantee a tax exemption.

The about-face could mean big changes for hundreds of millions of users who rely on Yahoo websites, services like email and other mobile applications. CEO Marissa Mayer plans to outline a cost-cutting reorganization late next month; many analysts speculate that Yahoo may simply sell off that business if the latest overhaul doesn’t bear fruit quickly

The uncertainty and reshuffling threaten more distractions at a time when Yahoo is already struggling in digital advertising against rivals such as Google and Facebook. It also may raise more doubts about whether Mayer will be able to turn around Yahoo, even though company Chairman Maynard Webb said Wednesday that the board of directors remains in her corner after three-and-half years on the job.

“The bottom line is the saga continues,” Macquarie Securities analyst Ben Schachter wrote in a Wednesday note titled “The Never-Ending Story.”

Yahoo’s new spinoff plan could be even more complicated than the original Aabaco spinoff. It may take more than a year before Yahoo shareholders get stock in a newly formed company that has yet to be named.

“This means they have squandered an entire year and now it’s going to take another year while the core business continues to get weaker,” BGC Financial analyst Colin Gillis said.

With Yahoo hanging in limbo, prospective bidders could emerge for the company’s Internet operations, which Wall Street has been valuing at next to nothing. Analysts believe Yahoo’s websites, mobile applications, ad services and well-known brand eventually could be worth $3 billion to $5 billion. Suitors might include AT&T Inc., Verizon Communications, Comcast Corp., IAC/InterActiveCorp and private equity firms that specialize in buying troubled companies. Webb, though, emphasized there are no plans to sell Yahoo’s Internet business, which he called “tremendously undervalued” in a Wednesday conference call. The best path forward, Webb said, involves “separating the Alibaba assets from our operating businesses and also turning around the performance in our operating business.”