Over the past few years, real estate has taken off, producing record highs in both prices and deal activity worldwide. Fueled in large part by cash flow and low interest rates, US commercial real estate transactions jumped 36% in the first half of 2015 to $225B, beating the pace set in 2006. Office building valuations in London, Hong Kong, Osaka and Chicago hit record highs on a price per square foot basis in Q2, reaching post-2009 highs in New York, Los Angeles, Berlin and Sydney, industry tracker Real Capital Analytics says. This rapid growth has fueled concern, as analysts draw comparisons to the housing boom—and crash—of the mid-2000s, the Wall Street Journal reports. The market is being watched closely by regulators and the Federal Reserve (pictured), which recently told Congress interest rates could rise later this year. Should this happen, property values could fall and possibly lead to a massive wave of mortgage defaults. [WSJ]