* U.S. stock indices up * Powell testifies before Congress on coronavirus and economy * Oil struggles to hold $75 a barrel level * Graphic: Global asset performance tmsnrt.rs/2yaDPgn * Graphic: World FX rates tmsnrt.rs/2egbfVh WASHINGTON, June 22 (Reuters) - Wall Street ticked upward on Tuesday as investors prepared for Federal Reserve Chairman Jerome Powell to flesh out his thinking on the U.S. economy, while oil and the dollar both struggled to hold early gains. Wall Street moved past mixed results in early trading to post solid gains by the afternoon, as investors awaited Powell’s testimony to a congressional panel. The Dow Jones Industrial Average rose 31.35 points, or 0.09%, the S&P 500 gained 14.95 points, or 0.35%. The Nasdaq Composite added 65.91 points, or 0.47%, which puts it on pace for another record closing high. The MSCI world equity index, which tracks shares in 45 nations, rose 3.52 points or 0.5%. Powell’s testimony provide investors with another chance to sort through the Fed’s thinking, after a policy meeting last week suggested Fed officials believed rates would rise sooner than previously indicated as inflation has ticked up. However, Powell has maintained that the Fed intends to keep up its unprecedented monetary support until the job market returns to normal. “As the cycle evolves, investors will increasingly divert their attention toward the potential party spoilers. A chief concern is inflation,” Tony DeSpirito, portfolio manager of Blackrock’s Equity Dividend Fund, wrote in a client note. “We expect fears of inflation will be enough to stoke volatility in stocks, even amid Fed assurances of continued accommodation.” Oil continued its solid run as investors anticipate an end to pandemic lockdowns will unleash pent-up travel demand. Brent crude futures rose above $75 a barrel for the first time in over two years in earlier trading before giving up some gains. It was last down $0.24, or 0.32%, at $74.66 a barrel, while U.S. crude was last down $0.62, or 0.84%, at $73.04 per barrel. BP Chief Executive Bernard Looney on Tuesday told Reuters there was “a very strong possibility” high price levels would be sustained over the coming years, “and if they do, it’s very good for our strategy.” In currency markets, the dollar gave up early gains to find itself sliding against major world currencies as investors waited to see if Powell pushes back on any view the Fed is prepping an earlier rate hike. The dollar index was down 0.17% in afternoon trading to 91.770 =USD, after hitting a two-month high on Friday. “I think today Powell is going to be able to reset his message,” said Edward Moya, senior market analyst at OANDA in New York. “Investors want to get a better view to see whether or not Powell does pull back a little bit of that extra hawkishness that we got last week.” The yen was last up 0.34%, at $110.6800, while the euro gained 0.16% at $1.1934. Bitcoin began making a comeback of sorts, climbing back above $30,000 after hitting lows not seen since January. The cryptocurrency last traded at $32,628, but has nearly halved in value over the last three months. Bitcoin and other cryptocurrencies came in for heavy selling on Monday, hurt by a tightening crackdown on trading and mining in China. In the bond markets, yields on benchmark 10-year U.S. Treasury notes were down slightly to 1.4801%. Spot gold prices fell $-4.4782 or -0.25%, to $1,778.47 an ounce. Reporting Pete Schroeder in Washington; Editing by Alison Williams, Angus MacSwan, William Maclean and Dan Grebler Our Standards: The Thomson Reuters Trust Principles.