FILE- This Tuesday, July 3, 2007 file photo shows the skyline of Washington, D.C., including the Washington Monument, the Lincoln Memorial and the U.S. Capitol. (Ron Edmonds/AP 2007 file)

In monetary terms, D.C.’s tech scene has been doing pretty well with investors lately: Local start-ups took in about $435 million between April and June 2017, compared with $298 million over the same period four years ago, according to Pitchbook investment data analyzed by the National Venture Capital Association.

But that funding is going to fewer and fewer companies each year, reflecting a “winner-take-all” start-up ecosystem where resources are concentrated at the top. Just 51 D.C.-area companies signed deals with venture capitalists between April and June, the second-worst quarter since 2013. That’s a far cry from a few years ago, when the number of deals per quarter tended to come in above 60.

“These numbers continue to reflect a hollowing-out of the middle in the D.C. area venture capital market,” said Jonathan Aberman, a local investor. “This is a chronic problem in our market. Chronic and it gets worse all the time.”

It’s a trend that’s been accelerating for a while. Almost half of all the D.C. area’s venture funding for the most recent quarter went to EverFi, which makes online education technology for universities.

In April, EverFi took in $190 million from a group of mainly West Coast investors, including U2 frontman Bono and Silicon Valley private equity fund TPG Growth. The company has created online courses in subjects such as alcohol safety and sexual assault prevention. It will use the case infusion to take on even more intractable problems, such as opioid abuse. The latest deal brought EverFi’s total capital raised over $250 million.

Before that the region’s start-ups were overshadowed by a $1 billion raise for OneWeb, a British start-up that houses much of its engineering operations in Northern Virginia. That funding came from the Japanese-based global telecommunications venture fund Softbank.

In 2015, the numbers were boosted by a $250 million funding round that went to local cybersecurity firm Tenable Network Security, a pot of money that again came from private-equity firms.

The shift mirrors what’s happening nationally.

Just 10 megadeals swallowed 20 percent of all U.S. start-up funding in the most recent quarter, the NVCA found, as investors seem to pool their money in a handful of perceived winners.

Despite recent legal challenges in key markets Airbnb picked up about $450 million in single investment round in March — more money than all of the D.C. area’s venture deals combined for that quarter.

A steady stream of public relations disasters didn’t stop Uber from attracting deep-pocketed new investors in 2017.

Further down the chain things are much less rosy. Funding for seed-stage start-ups — the cash-strapped, unproven firms in their earliest phases of growth — has declined for eight consecutive quarters nationally, erasing half of that market segment’s value since 2015.

Local investors point to a confluence of economic factors that are turning the technology industry into a winner-take-all market. One reason is the increased role of private-equity firms in funding proven, late-stage companies. Growing tech firms used to cash out by trading publicly on the stock market.

Now they are more likely to stay private, raising the capital they need from private-equity firms. Start-up founders often prefer that option because it spares them the hassle and added transparency of taking a company public.

Another contributing factor is the tendency of larger venture funds to favor more experienced founders, especially at the seed-stage level.

Some of the region’s biggest funding rounds in recent years went to veteran cybersecurity executives filtering out large cybersecurity companies after being bought out.

John Czupak, who was a senior vice president at a cybersecurity firm called Sourcefire before it sold to Cisco for $2.7 billion, was able to immediately pick up about $20 million from investors after he founded his new firm in 2015. Dave Merkel, who was chief technology officer of Mandiant before it sold to West Coast cybersecurity firm FireEye for about $1 billion, got $7.5 million for his company before the team had a single customer.

More recently a $17 million round of funding announced Thursday went to Framebridge, which is headed by Susan Tynan, a former LivingSocial executive.