Europe\'s main stock markets rose slightly on Wednesday as traders looked ahead to more testimony on the US economy from Federal Reserve Chairman Ben Bernanke and digested a unique German bond auction. London\'s FTSE 100 benchmark index of leading shares edged up 0.07 percent to 5,633.10 points in late morning trade. Frankfurt\'s DAX 30 index gained 0.14 percent to 6,586.56 points and in Paris the CAC 40 won 0.49 percent to 3,192.43. \"European markets have registered mild gains today on hopes that Fed chairman Bernanke will reveal more details on the central bank\'s stance on upcoming easing measures at his second day before US Congress,\" said Ishaq Siddiqi, an analyst at ETX Capital trading group. European stock markets had closed narrowly mixed on Tuesday, giving up modest early gains after Bernanke gave a gloomy outlook on the US economy. In prepared testimony to Congress, Bernanke conceded that US economic data had been \"disappointing\" and that a future reduction in unemployment would likely prove \"frustratingly slow.\" He also forecast slower growth for this year and next and painted a future replete with pitfalls both domestic and from Europe. \"Given that growth is projected to be not much above the rate needed to absorb new entrants into the labor force, the reduction in the unemployment rate seems likely to be frustratingly slow,\" he said in his semi-annual testimony. Meanwhile in foreign exchange deals on Wednesday, the European single currency fell to $1.2263 from $1.2292 late in New York on Tuesday. In a surprise move, investors have paid to lend Germany money for two years for the first time at an auction, the country\'s central bank said, as they flocked to the safe haven of Europe\'s top economy. The yield or rate on the auction of two-year debt was a record low of minus 0.06 percent, the Bundesbank, which organised the auction, said in a statement on Wednesday. A negative yield means that investors are actually paying to lend Germany money. \"In view of the ongoing market tensions, investors are continuing to look for quality and security. That was decisive factor in the success of this issue,\" said a spokesman for the Federal Finance Agency, which manages Germany\'s debt. German Chancellor Angela Merkel meanwhile said she was \"optimistic,\" but could not be certain that the \"European project\" would work, in a video interview published on Wednesday. \"We have of course not yet organised the European project in such a way that we can be sure it will work, work well. That means we need to keep working on this. We have much to do, but I am optimistic that we will succeed,\" she said. Speaking in an interview broadcast on the website of her conservative CDU party, Merkel added Germany could only do well economically when its European partners are prospering. \"Therefore we are working so hard to overcome the debt crisis and the competitiveness crisis,\" she said. Bailed-out eurozone member Portugal on Wednesday raised two billion euros ($2.5 billion) via six- and 12-month debt auctions at lower rates, the Treasury and government debt agency said. Portugal is able to only access short-term capital markets as it tries to get its finances in order with the help of a 78-billion-euro rescue package drawn up by the European Union and International Monetary Fund. In company news, the share price of London-based HSBC fell 0.86 percent to 542.7 pence after a top executive resigned over the banking giant\'s failure to control money laundering and terrorist financing. Europe\'s biggest bank apologised Tuesday for failing to apply anti-laundering rules as US lawmakers accused it of giving Iran, terrorists and drug dealers access to the US financial system.