Which of the following statements is correct?
1) I am working at ABN
2) I am working in ABN
where to use "at" and where to use "in". Please explain.
I presume that ABN is a company's name.
Either is fine; #1 is more common. #1 considers ABN a point location; #2 considers ABN a two- or three-dimensional location. The difference is moot here.