The selloff at Ford is gaining momentum.

The automaker's shares fell 3.4 percent Tuesday to close at $8.95, finishing the day under $9 for the first time since August of 2012. The stock is down more than 28 percent so far this year.

While analysts give a host of reasons for Ford's slide, the single biggest factor is the uncertainty surround CEO Jim Hackett's plan to restructure the Detroit company. Hackett and his management team have yet to disclose exactly how they will re-shape the automaker, though it will clearly be a leaner and more focused company.

"There's still a lot of uncertainty about Hackett's plan and vision," said Dave Whiston, an auto analyst with Morningstar.

Pressure has been building on Ford ever since the company reported lackluster earnings for the second quarter and announced it would postpone an analyst meeting in September. That meeting is when Hackett was widely expected to roll out details about the restructuring.