When China speaks now, the world’s traders jump.

By uttering just a few words yesterday, Beijing showed it’s got the economic clout to rally the world’s battered stock markets out of their costly tailspin, even if the country did cause the rout in the first place with earlier misstatements.

Shares soared all day in major capitals after Chinese officials denied alarming media reports the prior day that China’s central bank would start dumping euros and eurobonds from its $2.5 trillion foreign currency reserves.

Those reports by the Financial Times and Reuters, quoting senior officials, triggered a broad sell-off of stocks and the euro.

Chinese officials moved quickly yesterday ahead of US trading to brand the reports as “groundless,” while reassuring investors that China remains very committed to the shaky euro.

That helped send the euro rising for the first time in days, as the show of confidence managed to temporarily curb the fear epidemic gripping investors. The euro rose to $1.2370 from $1.2193 the prior day.

The Dow Jones industrial average zoomed nearly 285 points, while the two other major US indexes posted gains well above 3 percent. European markets rose between 3 percent and 4 percent.

Financials led the advances, but nearly all stocks in the major US indexes recorded gains yesterday.

Investors ignored a government report showing the economy grew at a lackluster 3 percent the first quarter, slower than the expected 3.2 percent.

The Dow climbed 284.54, or 2.9 percent, to 10,258.99. The Standard & Poor’s 500 index gained 3.3 percent to 1,103.06, or 35.11. The Nasdaq rose 3.7 percent to 2,277.68, or 81.80, making it the only index in the black, year-to-date.

The Dow is still down 1.6 percent for the year-to-date, and the S&P is down about 1.1 percent.

But for the 52-week period, investors still have bullish double-digit gains. The Dow and S&P are ahead nearly 24 percent each, while the Nasdaq is up about 32 percent.

Among big winners, Microsoft jumped 4 percent to $26 following an upgrade by an analyst. Two big retailers beat analysts’ expectations for earnings, with Costco jumping 4.9 percent to $58.74 and Tiffany climbing 7.5 percent to $46.86.

With a runaway oil well in the Gulf of Mexico slowing its damage, two of its operators gained: Halliburton rose 4.7 percent to $26.99 while BP climbed 7 percent to $45.38. Citigroup rose 4.2 percent to $4.02. Bank of America increased 4.6 percent to $16.18. Crude oil rose 4.2 percent to $74.53. paul.tharp@nypost.com