Key TakeawaysShares of Ally Financial plunged Tuesday as its chief financial officer said the company's auto loan portfolio is struggling.Delinquencies and net charge-offs were higher than expected in July and August, CFO Russ Hutchinson said during an investor conference Tuesday.Hutchinson said the bank expects net charge-offs to continue rising in the coming months . Ally Financial (ALLY) stock sank sharply after the bank's chief financial officer said at an investor conference that consumers are struggli ...