The word “trillions” gets thrown around a lot when people refer to real estate as an asset class. Broadly speaking, real estate is the largest asset class in the U.S. worth an estimated $40 trillion according to this December 2014 report from the Federal Reserve. To get specific, residential housing is the single largest “tangible” U.S. real estate asset, worth roughly $23 trillion, and commercial real estate accounts for another $15 trillion. To put this in perspective, as an asset class, real estate is meaningfully larger than other U.S. heavyweight industries like fixed income, equity and health care. Real estate lending is by far the largest lending category, belittling credit card debt by orders of magnitude. Residential mortgages alone accounted for nearly $12 trillion as of December 2014 compared with $882 billion in credit card debt.

http://techcrunch.com/2015/02/10/the-impending-opportunity-in-real-estate-technology/