Answered by Steve, Hiring Expert at Caterpillar Inc., on Friday, July 18, 2014
Although I would not include it in the Thank You correspondence, it is perfectly acceptable for you to inquire about pay if you have been formally offered the internship. You should approach the topic in a separate conversation, preferably by phone, but do so in a way that does not sound like you are trying to negotiate. In a polite manner, simply state something to the effect of 'this did not come up in our previous conversations, but I was curious about the compensation, if any, for this internship. Can you share that with me?' It depends on the company, but most internships are paid internships today. You are perfectly OK to inquire about this.