Trader Gregory Rowe on the floor of the New York Stock Exchange on Jan. 20, 2016. (Richard Drew/AP)

Global markets staged another wild ride Wednesday as stocks plunged and then whiplashed into a late recovery that fell short of halting a weeks-long losing streak.

The turbulent sell-off was ignited by familiar fears, including China’s weakening economy and oil prices that have plunged nearly 30 percent so far this year.

But the uncertainty has revealed fresh anxieties for one of the bright spots of the U.S. recovery: the technology sector, whose dependence on lofty valuations and risky investments appears headed for a reckoning some have thought was overdue.

Tech entrepreneurs who have relied on funding from deep-pocketed private investors are having trouble attracting the same interest now because of worries their companies have been overvalued amid a turn toward rockier markets. Larger firms such as Uber and Airbnb have sidestepped the markets altogether by avoiding initial public offerings.

Their reluctance is likely to trigger a wider pause, denying funds for the innovators that disrupt industries and create new markets. Many worry it will become more difficult for start-ups with promising but untested ideas to gain traction in the marketplace, forcing some to the sidelines.

The slump in oil prices continued to drive shares lower on global markets Jan. 20. (Reuters)

“Private investing has not dried up,” said Lise Buyer, founder of the Class V Group, a public-offering consultant in Silicon Valley. “It is just that people are sobering up.”

U.S. trading floors are usually bustling by now with young companies ready to make their Wall Street debuts. But the first scheduled public offering of the year, for online lending service Elevate Credit, was postponed late Wednesday because of worries about volatile markets.

All told, in 2016, only four companies have indicated they are prepared to go public, compared with the 12 to 14 that typically declare their intentions by this time of the year, according to Renaissance Capital, an IPO research firm.

None of the four are valued at more than $700 million, relatively small by the standards of the blockbuster offerings in recent years.

Investors’ demand for growing young companies helped spur the advent of “unicorns” — tech companies valued at $1 billion or more because of their promise of becoming the stars of tomorrow.

But now investors no longer seem so optimistic. They are preparing for a market with higher interest rates and slower growth trajectories, as evidenced by oil prices that plunged nearly 7 percent Wednesday to $26.55 a barrel, the lowest level since 2003.

The uncertainty blanketing the market is making raising money more difficult, analysts said, as investors place a higher value on profits rather than on dreamy forecasts of growth.

The total cash invested in private companies fell 30 percent, to $27.3 billion, in the last quarter of 2015 compared with the previous quarter, the research firm CB Insights said.

Tech entrepreneurs, analysts said, are entering a time of “down rounds” in which investors are lowering their estimates of what a company is worth. Jay Ritter, a University of Florida business professor who tracks IPO data, said some private tech firms are overvalued by 10 to 20 percent.

The location-sharing app Foursquare recently had to chop its market value in half. Another tech start-up, the two-year-old food-delivery service DoorDash, was struggling last year to convince venture capitalists that it was a unicorn and now has had to lower its valuation to $600 million, according to Bloomberg News.

“The market has gotten off to a terrible start in 2016, but it is also taking no prisoners when it comes to separating the unicorns from the donkeys,” said Richard Windsor, an analyst at Edison Investment Research.

The number of upcoming public debuts is still high compared with the aftermath of the last big, bursting tech bubble in 2000. “Good companies will be able to get out even within prevailing bad market conditions,” said Alan Jones, a partner at PricewaterhouseCoopers.

But some of the few tech firms that have braved the stock market have found themselves quickly stung. When file-sharing service Box went public last year, the company’s stock jumped — but it then lost half its value over the next year. Shares of Etsy, the online artisanal-wares bazaar that went public last year, have fallen 70 percent.

Even with Wednesday’s comeback, the global sell-off has extended a volatile streak that has marked one of the worst starts to a year in market history. The three major U.S. indexes have tumbled about 10 percent in the past three weeks.

The Dow Jones industrial average, an index of 30 stocks, fell Wednesday by more than 560 points before rallying to 15,766.74, a loss of about 1.6 percent.

The Standard & Poor’s 500-stock index, a broader look at the market, slipped about 1.2 percent, and the tech-heavy Nasdaq composite index fought back heavy losses to close only slightly lower.

The panicked sell-off touched every corner of American industry, most notably energy, raw materials, finance and retail. Even companies posting encouraging results were hit: Video streaming giant Netflix, which told Wall Street this week that its earnings and international subscriber base had grown more than expected, nevertheless saw its shares fall more than 6 percent Wednesday before rallying to close slightly down.

Other technology giants saw similar turbulence. Facebook’s stock fell more than 5 percent before recovering slightly to a loss of less than 1 percent. Apple shares fell about 3 percent, to their lowest level since the summer of 2014, before bouncing back to a small gain.

An increasingly sluggish China has touched off fears of a hard landing for the world’s second-largest economy that could ripple outward and harm the many companies that rely on its exports and spending for business.

For the third time in less than a year, the International Monetary Fund this week trimmed its projections for global growth, pointing to a recent Beijing report that showed China’s economy grew in 2015 at its slowest rate in more than two decades.

The International Energy Agency, a global oil adviser, said Tuesday that crude-oil prices would continue to sink this year if suppliers in countries such as Iran keep pumping, creating a glut that could force the oil market to “drown in oversupply.”

Slumping energy prices have helped lower the cost of living in the United States, with December showing the smallest yearly increase in the consumer price index in seven years, the Labor Department said Wednesday.

Investors flocked during the sell-off to the relative safety of gold and government bonds, with yields on 10-year U.S. Treasury notes falling just below 2 percent Wednesday. The yields fall as prices rise.

Economists on Wednesday pushed to cool down the heated sell-off by pointing to more optimistic fundamentals, including the nation’s strengthening employment rate and the industry boost of lower fuel costs.

“The sell-off is simply happening too fast, which signals panic selling more than reasoned investment decisions. . . . It can’t last,” Chris Rupkey, chief financial analyst at MUFG Union Bank, told investors. “This is overdone, and overdone, hard-down market sell-offs don’t hold.”

Other investment managers sought to calm traders unnerved by heavy volatility following several years of market strength after the global financial crisis.

Although he acknowledged that many had “fears of a full-scale recession,” Chris Hyzy, a chief investment officer at Bank of America Merrill Lynch, wrote Wednesday in a note to investors that “the 80-month-long economic expansion is still alive.”

Merle reported from New York.