The new year will see the undercut get a modern face-lift with refined touches, updating a haircut that originated in the 1920's. The key characteristics to this style are the short sides and short back, with some length through the top.
According to the Business Insider online, a barber on Wall Street attributed most of the styles belonging to younger guys, especially traders, who like to look "flashy". Another hairstylist who works downtown on Wall Street says it may be due to the bad economy and they're just getting fewer haircuts. Another opinion was that it's the "Mad Men" trend. Interesting.
If you feel you can carry it off guys, go for it. But please - don't do it without a strong dose of suavity and a glass of the finest scotch in your hand.