Stocks are closing solidly higher on Wall Street, giving the market its biggest gain in a month, as hopes grow that Britons will vote to remain in the European Union. European markets and the British pound also rose Thursday as Britons went to the polls, the AP reports. US government bond prices fell, sending yields higher. Gold fell. Banks posted big gains. Citigroup rose 4% and Bank of America climbed 3%. The Dow Jones industrial average rose 230 points, or 1.3%, to 18,011. It was the Dow's first close above 18,000 in two weeks. The Standard & Poor's 500 index gained 27 points, or 1.3%, to 2,113. The Nasdaq composite climbed 76 points, or 1.6%, to 4,910. The yield on the 10-year Treasury note rose to 1.74%.