Getting a good return on investments in the office sector may become a little harder over the next few years, but it should still be possible as long as you bet on markets with outsized rent growth. Where are these markets? A new report from real estate services firm CBRE answers that question. Here are the 10 U.S. markets that experienced the highest growth in office rents for class-A buildings year-over-year. The average growth globally was 2.0 percent. The average growth in the Americas was 3.4 percent.