The explosion in billion-dollar tech unicorns really kicked off in March


It seems like 2015 was the year of billion-dollar private tech companies, or "unicorns." More than 40 new companies joined the club this year.


Goldman Sachs charted the number of unicorns that existed in every month since Jan. 14. There was a notable acceleration starting in March 2015. Until then, it took about seven months for 20 new unicorns to be created. Since then, it's taken only three to four months.

With the fed raising interest rates, though, the unicorn boom could finally be set to end.

COTD 12.24.15

Goldman Sachs/WSJ