Okay, let’s break it down. As a CPA with 10+ years of experience in financial reporting and auditing, Karen can charge a premium rate. The fact that she has expertise in US GAAP, Sarbanes-Oxley Act, and internal controls makes her highly sought after. Her location in Baltimore, MD, is also a plus. Considering these factors, I estimate her hourly rate to be around $125, which is slightly below the national average for CPAs with similar experience and expertise. However, her certification and skills justify a rate that's competitive in the market.