Analysts say government's financial rescues have fueled conspiracy theories. The unusual circumstances that led the U.S. market to rally powerfully in 2009 might be explained by secret government moves to buy stocks, according to Charles Biderman, the founder and chief executive of TrimTabs, a research firm that tracks liquidity flows in the market. "We cannot identify the source of the new money that pushed stock prices up so far so fast," Biderman said . The source of approximately $600 billion net new cash necessary to lift the market's overall capitalization by $6 trillion last year could not be identified by...