* Shares rise after Alcoa's solid start to U.S. earnings season * Greek aid deal initially lifts euro, euro zone debt * Oil eases as supply boosts outweigh Egypt worries By Herbert Lash NEW YORK, July 9 (Reuters) - Global equity markets extended gains on Tuesday and the dollar traded near a three-year high, spurred by an optimistic tone at a good start to the U.S. earnings season after last week's strong jobs data. Equity markets reacted favorably after aluminum producer Alcoa, traditionally the first major U.S. company to report quarterly earnings, posted adjusted profit and revenue above expectations after markets closed on Monday. Alcoa said it sees solid growth in global demand this year. "We've got a risk-on theme with Alcoa's better-than-expected profits," said Jordan Hiscott, a trader at Gekko Global Markets. "You are seeing people reallocating assets into equities, they are definitely very popular at the moment." Europe's broad FTSEurofirst 300 index of leading regional companies hit its highest in a month before paring some gains as a deal to provide Greece the latest 6.8 billion euro ($8.7 billion) installment of its bailout bolstered the upbeat mood. MSCI's all-country world equity index rose 0.72 percent. According to Thomson Reuters data through Tuesday morning, analysts' expectations call for S&P 500 earnings to increase 2.9 percent in the second quarter from a year ago, while revenue is forecast to have increased 1.5 percent from a year ago. The Dow Jones industrial average rose 74.3 points or 0.49 percent to 15,298.99, the S&P 500 gained 8.88 points or 0.54 percent to 1,649.34, and the Nasdaq Composite added 10.14 points or 0.29 percent to 3,494.97. The Greek aid deal helped Greek and Portuguese bonds add to their gains of the last few days. It also helped lift the euro off the seven-week low it has been at since the European Central Bank made clear last week it is prepared to cut interest rates again. The dollar rose toward recent three-year highs against a basket of currencies, with more investors betting on further gains as the Federal Reserve prepares to reduce its stimulus program. The dollar's biggest gains were against the British pound, after weaker-than-expected UK data drove sterling close to a three-year low and highlighted the divergence between UK and U.S. monetary policy. The dollar index, which measures the greenback against a currency basket, was up 0.17 percent at 84.336, having earlier hit 84.085 on a dip in U.S. Treasury yields. The euro was down 0.15 percent at $1.2850, holding above Friday's seven-week trough of $1.2806. The single currency found some support after Greece secured aid that will prevent it from defaulting in August. U.S. Treasuries prices held steady as investors prepared to make room for a $32 billion three-year note sale, the first part of this week's $66 billion in coupon-bearing supply. The 10-year U.S. Treasury note was 3/32 higher in price to yield 2.630 percent. Brent crude oil fell toward $107 a barrel as worries about supply disruptions in the Middle East eased, though investors were wary that more negative headlines from Egypt could trigger renewed volatility. Brent fell 13 cents to $107.30 after slipping to a session low of $106.85 earlier. U.S. crude fell 20 cents to $102.94.