* Sony Financial falls after earnings guidance disappoints * SoftBank slips, Sprint permitted discussions with Dish By Dominic Lau TOKYO, May 21 (Reuters) - Japan's Nikkei average eased from a 5-1/2-year high on Tuesday after Wall Street gave up earlier gains to end flat and the dollar slipped against the yen on caution before U.S. Federal Reserve Chairman Ben Bernanke fronts a Congressional hearing. The Nikkei slipped 0.2 percent to 15,337.42. The benchmark has rallied 47.5 percent this year, and it has risen 8 percent since May 9, when the dollar broke above the 100-yen mark. "There is a little bit of profit-taking. There was a little bit of weakness in the U.S.," said a senior dealer at a foreign brokerage, noting that the underlying tone of the market remained firm. U.S. stocks ended little changed on Monday, with indexes hovering near record levels as concerns about a correction wiped out earlier gains made on a flurry of acquisitions. The Bank of Japan is expected to stand pat on monetary policy when it concludes a two-day meeting on Wednesday, but it may seek ways to calm the bond market over the recent volatility it has experienced. Bernanke's testimony in Congress on Wednesday was also a focus for global financial markets after recent comments by Fed officials drove speculation the U.S. central bank could trim its asset purchase programme sooner than first thought. The yen last traded at 102.47 yen to the dollar on Tuesday, rebounding from a 4-1/2-year low of 103.32 hit on Friday. But there are signs that many firms in export-driven Japan Inc, having got the weaker yen they craved, now want the currency to either stabilise or recover ground, rather than continue a slide that will increasingly raise their costs. The broader Topix index was flat at 1,269.77. SoftBank Corp lost 1.6 percent. U.S. wireless operator Sprint Nextel Corp said it has received a waiver from SoftBank allowing it to engage with Dish Network Corp in discussions over a proposed offer, although Sprint said its recommendation in favour of the SoftBank offer has not changed. Sony Financial Holdings Inc dropped 2.7 percent after it forecast a net income of 37 billion yen for the current business ending March 2014, below an average of 43.05 billion yen from 11 analysts polled by Thomson Reuters I/B/E/S. In terms of valuations, Japanese equities carry a 12-month forward price-to-earnings ratio of 15.9, a level not seen since May 2010 but still below its 10-year average of 16.3, according to Thomson Reuters Datastream.