Stocks posted their first loss of the week as President Obama and congressional Republicans sniped at each other as a deadline to avoid tax increases and government spending cuts drew closer. Obama said he and House Speaker John Boehner were ‘pretty close’ to a deal to avoid the so-called fiscal cliff, but the Republicans keep finding ways ‘to say no as opposed to finding ways to say yes.’ A defiant Boehner called for Obama to offer a plan balanced between spending cuts and tax hikes. The S&P 500 had gained more than 2% over the previous two days in part because of optimism about a deal — optimism that seemed to melt away on Wednesday.