Cornerstone, CPA At our firm, all of the pieces come together. You get the depth of experience gained at the top local and international firms, combined with the individual attention that you need to succeed. We have been licensed and practicing Certified Public Accountants since 1996. This experience is offered to each of our clients. We do not send lower level staff to advise you. We like what we do and we treat each situation as if it were our own.