Using a case study without company's permission In addition to academic work, I have done private work in industry that is directly related to the material I'm presenting. For one of my lessons, I would like to do a case study, where I take a problem posed by one of my clients and discuss the thought process and methodology I utilized to solve the problem. 

For the case study, I do not intend to reference the company name (instead referring to them as "Company X"). I intended to keep the industry and solution mostly the same, although I would not present or divulge any source code from the deliverable or data from the actual company.

My concern is that the technology I developed for the company may be considered proprietary or a trade secret by the company. While I wouldn't be presenting enough for someone to identify the client or exactly how I solved the problem, I fear that I may no longer have the right to present on this information without explicit permission from the former client. 

To enumerate, my question has the following facets:


Do I have an ethical or legal obligation (in the United States) to ask the former client's permission before doing an anonymized case study, even if none of their data or my deliverable is presented?
Is there any standard or rule of thumb for using personal real-world examples in an academic setting while respecting a company's right to maintain trade secrets?


To clarify, there was no NDA/Intellectual Property transfer document or other legal document that could complicate the situation. The work was performed as a independent contractor in the United States.
Honestly, I would not do this.
I am not familiar with US law so I cannot give you any legal advice. However, there are several other non-legal risks you have to bear.

According to your description, you intend to stick closely to the real case in your presentation. The students might be intelligent enough to draw the necessary conclusions or could even be involved with the company. I would not risk this.

As a result, the company could get the impression, that you have leaked confidential data to the students. Indepdent from the question whether this is illegal or legal, facing a lawsuit can easily have a disastrous effect on your career. Furthermore, this can also result in loss of trust, again impacting your career.

I only see two possible options here:


You ask your former client for a written(!) permission
You largely modify your example / problem


Both methods, when done correctly, will save you from a lot of risk.

I had a similar problem, when I wanted to write a paper about work I did for an industry partner. Usually, this is quite strict, since nobody wants to have their confidential solutions published. However, I was able to chance the problem and solution sufficiently. Despite the same ideas were used, the original problem and client remained hidden and I was able to publish my ideas. This was quite a lot of work to do, since I had to redo most of the code and experiments. Altogether, this was worth the effort since I do not have any fear of legal consequences and we still have a good relationship to our clients.