(Eduardo Munoz/Reuters)

When many people hear that the tech bubble is going to burst, they harken back to 2000 or 2008 when the floor fell out of the tech industry.

"Other than the fact that they are cycles of eight, the three sort of periods are very, very different," warns Hemant Taneja, managing director of General Catalyst Partners.

The first collapse came at the end of the dot-com bubble in 2000 after companies had gone public, only to disintegrate and run out of money completely.

The subsequent bubble burst came in 2008 when there was a financial crisis that rocked the country across all industries.

Now in 2016, venture capitalists are worried that a slowdown is happening again. Faced with some rockiness in the public markets, the tech community has shifted from greed to fear — yet the capital is still there to be invested.

"In 2008, what really happened was the financial crisis. There was good reason why there was a liquidity crisis and capital started to get sparse," Taneja said. "When I think about 2016, I can't think of any event that are really that impactful to the venture world."

That's good news for some companies

So why all the fear?

In 2016, there are more than 160 "unicorn" companies that are now worth more than $1 billion.

"The venture community has realized that a number of companies were funded at valuations that were far ahead of their fundamental progress as businesses, and that some of those companies are not actually that great fundamental businesses," said Sequoia Capital partner Alfred Lin.

Not all of the unicorns are unworthy of their rich valuations, of course. But there is a growing acknowledgement that the buzz to reach the billion-dollar valuation got out of control.

"What really happened was we were fixated on this word unicorn," Taneja said.

(Samantha Lee/Business Insider)

Sequoia's Lin started feeling the tremors of the shift after July 4, but it didn't really enter the public's conscience until after Square's IPO in November. The payments company, valued at $6 billion, went public below its last private-valuation price. And not only was it priced below, but it had a "dirty term" of a ratchet, designed to protect its late-stage investors.

The IPO intensified two fears already creeping into the venture-capital community: that these startups might be valued too high, and some companies might have taken dirty terms to get the big-number valuation.

Now in 2016, there's been a slowdown, and the VCs we spoke to describe the path ahead only as bumpy.

"I wouldn't say the easy money's gone, but the price of oxygen has increased," said Keith Rabois, a partner at Khosla Ventures.