GLOBAL MARKETS-Stocks little changed with eyes on Greece; oil off

* Healthcare stocks lead Wall St up on Supreme Court ruling

* Iran talks drag crude prices lower (Updates trading, adds U.S. markets, changes byline, dateline, previous LONDON)

By Rodrigo Campos

NEW YORK, June 25 (Reuters) - A Supreme Court ruling upholding tax subsidies boosted some U.S. healthcare stocks to fresh highs on Thursday, while key global equity markets were little changed following a proposal by Greece's creditors to avoid a Greek debt default.

Oil prices fell on concerns over the possible impact of Greece's debt crisis on European energy demand and the prospect of Iranian oil adding to a global glut if sanctions are lifted.

Greece's international creditors presented a cash-for-reform proposal to euro zone finance ministers in a showdown with Athens, after negotiations failed to yield a plan to avert a default.

"There is still a bit of optimism left that a deal can be done ... A failure to reach a deal is certainly not priced into the market just yet," Peregrine & Black senior analyst Markus Huber said.

Market participants had assumed this week that a deal would eventually be reached after European officials said on Monday and Tuesday a proposal from Greece was a good basis for talks.

The differences between Greece's proposal and that of its creditors aren't big enough to justify failing to reach an agreement, a senior Greek government official said.

On Wall Street, hospital and other healthcare shares surged, with several hitting all-time peaks, after the U.S. Supreme Court upheld tax subsidies that are key to President Barack Obama's signature healthcare law.

"The hospital stocks all reacted positively to the news, which isn't a surprise. While any change in policy would've been a surprise, affirming the status quo removes a lot of uncertainty from the sector," said Michael O'Rourke, chief market strategist at JonesTrading in Greenwich, Connecticut.

The Dow Jones industrial average rose 25.12 points, or 0.14 percent, to 17,991.19, the S&P 500 gained 4.76 points, or 0.23 percent, to 2,113.34 and the Nasdaq Composite added 13.96 points, or 0.27 percent, to 5,136.37.

The pan-European FTSEurofirst 300 index was down 0.2 percent. An MSCI gauge of major global markets added less than 0.1 percent.

OIL SLIDES

In commodities markets, crude prices fell, with traders eyeing progress toward a June 30 deadline for an Iran nuclear accord that would be key to lifting Western sanctions on Tehran's oil exports.

"Even (Taiwan OTC: 6436.TWO - news) if it does take Iran a year or more to return output and exports to pre-sanctions levels, the anticipation of this additional supply should still affect prices now," Capital Economics said.

"The prospect of another 1 million bpd increase in supply from Iran ... could easily drag (Brent) prices below $60 again."

Brent fell 0.7 percent to $62.99 a barrel and U.S. crude was down 1 percent at $59.68 a barrel.

Spot gold edged lower, down for a fifth straight session, while copper prices rose 0.3 percent.

EURO HOLDS

The euro was little changed against the U.S. dollar, even after data showed U.S. consumer spending recorded its largest increase in nearly six years on strong demand for automobiles and other big-ticket items.

The euro was down 0.07 percent at $1.1197.

"Watching Greek headlines. That's kind of holding markets back," said Vassili Serebriakov, currency strategist at BNP (Paris: FR0000131104 - news) Paribas in New York.

"This week we have seen appetite to start rebuilding dollar long positions," he said. "Markets are feeling more confident that U.S. data is rebounding and the dollar will do well."

U.S. benchmark 10-year Treasury notes were last down 14/32 to yield 2.4197 percent, from a yield of 2.371 percent late Wednesday. (Additional reporting by Ryan Vlastelica, Dan Bases, Sam Forgione, Barani Krishnan and European desks; Editing by Bernadette Baum)