General Motors reported earnings today that appeared non-eventful on the surface. Upon further inspection there are some underlying concerns, including a glaring one-time event that stands out. That is an adjustment to earnings with a tax benefit (as opposed to paying taxes) of $35 billion for a "deferred tax valuation release." This was coupled with a goodwill impairment charge of about $27 billion, which allows GM to reduce the previously unusually high goodwill assets that were recorded on its balance sheet. GM uses non-GAAP (Generally Accepted Accounting Principles) to calculate its calendar year operating income of $7.9 billion. The GAAP...