Most company reports or accounts are found online as PDF documents. In general, any PDF which you find online is probably available on paper and can be referenced as a paper source.

Company reports or accounts can be referenced as paper BOOKS. If you are able to find the information you need to do this then there is no need to give an electronic reference.

In most cases the company which is the author of the report is also the publisher. If a place of publication is not obvious on the document then look on the website of the company for their headquarters and use that as the place of publication.

In the unlikely event that it proves impossible to find the information you need to give a full paper book reference, then reference the report in the same way as you would reference a web page.