With the current stock market bull run reaching nearly 10 years in length, it’s understandable that many investors are nervous about the end of the party coming sooner than later. However, as UBS notes in its latest report, there is also growing concern about another prominent bubble that’s been in the works since the aftermath of the financial crisis. Large amounts of easy money have fueled real estate bubbles in the world’s major cities – and the Swiss investment bank now sees the property markets in six global cities as being at risk.