If Ford Motor’s stock wasn’t priced for perfection, it was certainly priced for something close to it. But after the auto maker’s warning at its annual investors’ day Monday of sharply lower profits, that no longer holds true: As of Tuesday afternoon, Ford shares were down 9.5% from where they ended Friday.

Ford’s expectation for pretax earnings of between $6 billion and $7 billion this year, versus its previous forecast of $7 billion to $8 billion, was disappointing. But it wasn’t entirely surprising given the company’s…