Difference between “with”, “at” and “for” with a business title and a company name

Question

The prepositions “with”, “at” and “for” are also used to associate a business title with a company's name. It seems that they are interchangeable, with no (significant) difference in meaning. The following examples taken from The New York Times website seem to confirm that:

Until now, said Justin Nielson, a senior analyst for the media research firm SNL Kagan, “there really hasn't been any direct competitor . . .

“The consumer is still deleveraging,” said Jason Goldberg, a senior analyst with Barclays. “It's not a lack of supply; it's a lack of demand.”

“There’s the party of fear and the party of despair,” Nikos Xydakis, a political analyst and an editor at Kathimerini daily, said.

Are they really the same as for meaning? If it isn't so, what is the difference between them?

Answer 1

The three prepositions imply three different things:

For emphasizes the employer-employee relationship. If I work for a company, they issue my paycheck, and they can fire me for poor performance.

At emphasizes the locale where I work. If I work at a company, I usually park in their parking lot, and work in their building each workday.

With emphasizes that I'm part of a team. If I work with a company, then that company's workers are my co-workers.

The words are essentially interchangeable in many contexts, because many of us do all three at the three time. If I was employed at Nike, for example, I could say that I work for Nike (they issue my paycheck), at Nike (I work in their building), and with Nike (I work with their employees). Quite often, saying one implies the other two.

One of the three prepositions may become less appropriate if one of those three conditions isn't true. If Nike hires me as an independent consultant or specialist, and they allow to me work from home, I might be less prone to use at. If I serve on an advisory board in a part-time, volunteer capacity, I might be more inclined to use with, and less inclined to use for.

Answer 2

They are used interchangeably. If you are an independent consultant, though, with sounds better than at or for, since your relationship with the company is not as an employee but as a separate business.

Answer 3

I have been taught that the right grammatical expression is work for company X. But I just Googled and work for and work at are the trends and even sites like glassdoor use work at. So I guess it is up to your taste. I would use work with when talking about group of people.

E.g:

You will work with programmers ,experts in their field, and top notch technologies.