Amid fears over slowing VC investment in tech ventures, new data finds that "unicorn" companies, or those valued at $1 billion or more, are winning more capital than ever before. The downside? Early-stage startups are suffering. 

On Thursday, PitchBook, Inc., a Seattle research firm, released its analysis of venture capital investment for the second quarter of 2016. A record 39 percent of VC dollars ($8.78 billion) went to unicorns, which is more than twice the $4.06 billion invested in the same period last year.

Meanwhile, the number of first financing rounds for startups dropped to just 525, (down 38 percent from 2015), as seed deal flow hit its lowest point in nearly five years. So far in 2016, just over one percent of startups with seed funding successfully closed Series A rounds -- the lowest amount recorded. 

"As VC fund sizes get bigger and bigger, there's a need to write bigger checks," said Garrett Black, a senior analyst at PitchBook. "It's never been more important for startups to focus on nailing product-market fit early, minimizing burn rates, etc., in order to increase their likelihood of receiving funding."

To his point, firms like Accel Partners, Insight Venture Partners, and Kleiner Perkins Caulfield & Byers poured large amounts of capital into fewer deals in the second quarter. Overall, VCs invested more than $20 billion across 1,906 deals.

The data further suggests that VCs are more interested in companies with proven business models, and less likely to take a gamble on tech startups with lofty goals. Uber, Pinterest, Snapchat and Slack were among the unicorn companies that scored investment in the second quarter of the year. (In May, Uber raised a massive $5.6 billion in its Series G funding for a reported $61 billion valuation, which accounts for about one quarter of the total capital invested, according to PitchBook.)

Meanwhile, Airbnb is reportedly seeking to raise funding at a $30 billion valuation. If successful, this would make the peer-to-peer lodgings service the second-highest valued private company in the U.S.