Article usage in a noun clause: "Tim Courtney, (a?) (the?) chief investment officer of Exencial Wealth Advisors, said.."

Question

I am struggling with using articles in noun clauses. I have seen some examples where an articles is omitted when the following noun is not even uncountable. For example:

"Tim Courtney, chief investment officer of Exencial Wealth Advisors, said: 'We're stockpiling commodities and demand is not picking up. It's kind of a depressing market.'"

Would it be correct if I write " Time Courtney, a chief investment officer of Exencial Wealth Advisors,..." with an article. I do not believe the word "officer" is uncountable.

Another example to further explain my problem: Mr. Smith, a teacher at Lincoln high school, has a phD degree in math. or Mr. Smith, teacher at Lincoln high school, has a phD degree in math.

Which one is grammatically correct? Or are both acceptable? or they simply carry different meanings.

Please help. Thank you.

Answer 1

Both are correct.

"Tim Courtney, chief investment officer of ... " sounds more authoritative, since we don't know whether he's the only chief investment officer, or one of the two chief investment officers, etc.

"Tim Courtney, a chief investment officer of ... " lets you know that he's one of many, which right away undermines his authority.