<prompt> Human: Over the weekend, I received a random, overnight mailing from my mortgage company in personal letter form from one of their Vice Presidents. In it, is an offer to save me a quarter percent on my mortgage that was originated back in Sept. 2015 with no attached costs to me, at least from what I can see. My biggest question is, WHY would they do this? The rate will go from 4.25 to 3.99 and over the remaining portion of my loan, it states I would save over 13k in interest in the same time period. They arent extending the payment terms so I still have 29 years and six months left. The monthly savings come to about 38. Sure, it all sounds like a no-brainer, this wasnt a third party offer from some random company, it is my original mortgage company even though it has since been sold to Fannie Mae. Ive read the fine print on the back and cant find anything that would change via the terms. Has anyone else had this happen to them before? Im leery, even if it comes from a trusted source and wanted to hear from reddit before I make the call to lower it. Thanks!  <response>: Its an incentive to stay with them, rather than refinance with another lender. 