* Bond prices fall; BoJ could scale back stimulus
* U.S. yield curve steepens; dollar nudged off 2-week lows
* U.S. stocks rise ahead of major earnings
* Oil volatile on U.S.-Iran row, while gold loses more luster (Updates to U.S. equity market close)
By Trevor Hunnicutt
NEW YORK, July 23 (Reuters) - Fear that U.S. and Japanese policymakers will scale back economic stimulus sent quivers through debt markets on Monday, while U.S. stocks gained ahead of major company earnings reports.
Bond yields climbed as investors forecast the Federal Reserve will continue raising interest rates due to stronger growth and inflation pressures despite U.S. President Donald Trump's criticism and after a Reuters report that the Bank of Japan (BoJ) is discussing modifying its huge stimulus program sent Japan's 10-year bond yield soaring near six-month highs.
The report rekindled anxiety about whether monetary policymakers will continue lending support to the global economy and piled pressure on investors navigating rising protectionism.
U.S. 10-year Treasury yields hit the highest in a month, trading at 2.9615 percent.
"It's all that concern investors have about the move from global quantitative easing to global quantitative tightening," said Rory McPherson, Psigma Investment Management Ltd's head of investment strategy.
"That fear gets stoked when you have reports such as this."
Sage Advisory Services Ltd President Bob Smith said there is no "800-pound gorilla" willing to absorb rising bond inventories. Several U.S. bond auctions are scheduled this week.
"You're sitting right in the dead of summer," he said.
"I don't think the superheroes are on the (trading) desks right now. They're probably on the beach."
The dollar index rose 0.19 percent off two-week lows it hit after Trump criticized Fed rate hikes and accused the European Union and China of manipulating their currencies.
Beijing said it does not intend to devalue the yuan to help exports.
"We see the latest news on trade policy as pointing to continued high risk of escalation between the U.S. and China, and a renewed focus of the Trump Administration on currency matters," Goldman Sachs analysts said.
Trump's warnings last week about excessive rate hikes also widened the gap between short- and long-term Treasury yields. That yield curve "steepening" accelerated on Monday, with yields on 30-year Treasuries 0.46 percentage point higher than their 2-year counterparts, the biggest gap in nearly a month.
Fed policy drives short-end Treasury yields, while inflation and growth expectations move longer-term yields. The gap has been shrinking this year, which some investors view as a cue for recession.
Trump's threats to slap duties on all $500 billion of U.S. imports from China triggered selloffs across global stock markets.
Yet the S&P 500 managed gains ahead of potentially blockbuster earnings.
Financials welcome steep yield curves because they borrow at short-term rates and lend over longer periods, profiting on the difference.
MSCI's gauge of stocks globally shed 0.01 percent, with equities broadly lower across Europe, Japan and emerging markets.
The Dow Jones Industrial Average fell 13.83 points, or 0.06 percent, to 25,044.29, the S&P 500 gained 5.15 points, or 0.18 percent, to 2,806.98 and the Nasdaq Composite added 21.68 points, or 0.28 percent, to 7,841.87.
Investors are bracing for a packed earnings week, including Facebook Inc's results, and a meeting on tariffs between European Commission President Jean-Claude Juncker and Trump.
Oil prices fell after earlier gains. Saudi Arabia and other producers could raise production before a November deadline for countries to comply with U.S. sanctions on Iranian crude sales, traders said.
U.S. crude settled down 0.54 percent at $67.89 per barrel and Brent ticked down 0.01 percent to $73.06.
Both copper and gold neared one-year lows. Copper - among the most sensitive to trade tensions - lost 0.32 percent, trading at $6,128.00 a tonne.
Spot gold dropped 0.6 percent to $1,224.31 an ounce. A strong greenback makes the metal, which is priced in dollars, more expensive to international buyers.
Reporting by Trevor Hunnicutt Additional reporting by Jessica Resnick-Ault, Helen Reid and Dhara Ranasinghe Editing by Nick Zieminski