Inside the Smart Game of Late Fundraising Rounds Late-stage capital is more common now. Here are 3 reasons why.

It used to be the walk of shame: startups raising Series D, E and even later rounds of investment. This was usually an indication that things weren't going as planned or that the window for a substantial acquisition or IPO had shut for macroeconomic reasons. While the letters associated with a round of private capital are somewhat arbitrary, the deeper you went into the alphabet, the more questions were asked about whether you had a viable business.

This is no longer the case. Today, mega-rounds of late-stage capital are common, driven by companies that are choosing to stay private longer. According to the National Venture Capital Association, the median time for venture-backed startups to exit more than doubled from 3.1 years in 2000 to 7.4 years in 2013.

Companies such as Airbnb, Dropbox and Uber have raised staggering amounts of capital in later rounds, eclipsing $1 billion in some cases. A decade ago, venture-backed companies would have been ecstatic to achieve a $1 billion valuation and cash out; now there are so many so-called "unicorns" that the private capital markets have adapted to tame the herd.