It's such a stupid lie as well. He already has a degree in accounting and has loads of relevant experience. Why lie about an additional degree?

What's happening here is liar's debt. Early in his career he must have made a decision to lie about his education, when no one was looking and when the chances of someone verifying the claim were low. He reused the lie on every subsequent job and it's stuck with him. It became encoded in the DNA of his professional reputation and he could not disabuse himself of it without making himself look the fool.

Now if the lie is recent and was used to get the head job at Yahoo - well then it's an even stupider lie. Why risk your professional reputation over something so trivial?