At some point soon, Ford ( F) shares will likely close at a higher price than General Motors' ( GM), reversing a decades-old pattern. The shift would be largely symbolic as Ford passed GM in market capitalization years ago, but meaningful to the extent that it would reflect the success of Ford's continuing effort to distance itself from its Detroit rival. On Thursday, Ford traded higher than GM at times during the day, but closed lower, down 6 cents to $1.81. GM closed down 34 cents to $1.86. As the share-price moves reflect, the two icons' different directions have rarely been more clearly delineated than during the past 24 hours. Wednesday evening, Ford said it is moving to restructure debt, reducing liabilities and future interest payments. Generally, such efforts are viewed positively, although initially they represent a distressed exchange for debt holders, who would not receive full value. Meanwhile, on Thursday, GM indicated in a filing that its auditor has raised "substantial doubt" about its ability to continue as a going concern. The disclosure, included in the company's 10-K filing with the Securities and Exchange Commission, said "recurring losses from operations, stockholders' deficit, and inability to generate sufficient cash flow to meet our obligations and sustain our operations raise substantial doubt about our ability to continue as a going concern." The company conceded that failure to execute its viability plan may force a bankruptcy -- assuming it does not receive more federal assistance. In truth, GM said last week, as it reported fourth-quarter earnings, that its auditors had raised the going concern question. And GM has said repeatedly that it cannot stay afloat without more government help.