* Investors looking for clarity on Fed stimulus program * Dollar index firmer but down from near three-year high * Yen dips after Japan minister says seeks 'balance' for currency * Commodities fall, gold and oil weaker on the day By Ryan Vlastelica NEW YORK, May 21 (Reuters) - Stock markets around the world edged higher on Tuesday amid signs of improving growth, even as uncertainties concerning monetary policy limited gains. The Dow and S&P 500 were at all-time highs while the dollar rose and gold fell. The euro was slightly higher, though a slowdown in British inflation sent sterling to a 7-week low on the view it could give the Bank of England more leeway to support the economy. The yen lost ground after a Japanese minister rowed back on remarks suggesting the currency had weakened enough. In the latest sign of improving sentiment, Goldman Sachs forecast further gains for the S&P 500 this year, expecting it to rise to 1,750 and then to 1,900 by the end of 2014. The benchmark index is currently at 1,670 after gains of 17 percent in 2013. Much of those gains have come on an accommodative monetary policy from the Federal Reserve, which analysts credit with making equities more attractive than other asset classes. The stimulus has pushed many financial markets to their highest levels in years, but in recent weeks Fed officials have started talking more openly about scaling back the bank's support. The usually dovish Chicago Fed President Charles Evans said on Monday that as long as the pick-up in the U.S. jobs market continued, he was "open-minded" about slowing the bank's bond-buying and mentioned the idea of simply halting it. Comments like that have made Wednesday's release of minutes from the U.S. central bank's last meeting and Fed Chairman Ben Bernanke's testimony in Congress the main focus for markets waiting for the first sign of a clear shift in attitude. Markets are "nervous" ahead of the testimony, "but not enough to take any action," said Kim Forrest, senior equity research analyst at Fort Pitt Capital Group in Pittsburgh. Economists expect Bernanke to deliver a steady message on the bank's policy. But any hint that it plans to scale back its support could unsettle markets. "With the economic numbers being pretty good in the States, there may be an easing back of QE (bond-buying stimulus) sooner rather than later," said Berkeley Futures associate director Richard Griffiths. DOLLAR, U.S. STOCKS UP The dollar was up 0.2 percent against a basket of major currencies. The Dow Jones industrial average was up 70.34 points, or 0.46 percent, at 15,405.62. The Standard & Poor's 500 Index was up 5.38 points, or 0.32 percent, at 1,671.67. The Nasdaq Composite Index was up 8.34 points, or 0.24 percent, at 3,504.77. U.S. equities were boosted by Home Depot, which raised its full-year profit outlook as it benefited from a recovery in the housing market. Financial shares were also higher, led by JPMorgan Chase & Co, which rose 1.8 percent to $53.22 after shareholders voted in support of Chairman and Chief Executive Jamie Dimon maintaining both roles, rather than splitting them. Top European shares ended 0.1 percent higher, extending a rally that took them to five-year highs on Monday. The MSCI all-country world equity index added 0.3 percent. The benchmark 10-year U.S. Treasury note was up 6/32, with the yield at 1.9437 percent. GREECE LIGHTENING If the Fed does tighten policy by slowing its bond-buying, benchmark bond yields would be pushed up. Safe-haven German Bund futures lost ground, dropping 0.2 percent. In Greece, 10-year yields fell below 30-year yields for the first time in three years, popping its bond curve back into a more normal shape in a sign that some are starting to believe the worst may be over for the euro zone's most troubled economy. "The perception of investors has changed," said ING strategist Alessandro Giansanti in Amsterdam. "There has been a change in trend in public finance policies. If the trend of reduction in the deficit continues, we cannot rule out that even next year (Greece) can come back to the market." YEN, METALS YO-YO Earlier in the day, Japan's Nikkei share index crept to a 5-1/2-year high. The yen shed some of Monday's gains after Japan's economy minister said his comments the previous day that the government was satisfied with the level of the currency had been misinterpreted. A recent slide in precious metals also resumed. Gold was down 1.4 percent as the stronger dollar left it facing its eighth fall in nine sessions. Silver dropped more than 3 percent. While low inflation prospects have dulled demand for the traditional hedge of gold, silver has fallen out of favor with investors recently as demand from the solar energy sector has also sagged and mining of the metal has increased. "The market was caught horribly short yesterday, so there was some buying this morning. But the dollar started to get stronger and gold didn't manage to break above $1,400, so sales started again," said Marex Spectron head trader David Govett. U.S. crude oil fell 0.6 percent on caution ahead of Bernanke's testimony while Brent crude fell 0.9 percent.