Optimists outnumber pessimists among U.S. investors

"[This year] has begun with the U.S. equity markets nearing or exceeding their pre-2008 highs, and consumer confidence has risen to new post-2008 highs," the report states. "So far in 2013, this optimism, combined with a widespread rotation away from fixed income products, has yielded strong results in equity products, potentially just in time for investors to buy high once again."

The heightened optimism of U.S. investors, the report adds, is reflected in increased net flows into equity mutual funds and exchanged-traded funds. In 2012, net flows totaled $66 billion, up from $11 billion in 2011, though down from the $101 billion recorded in 2010.

The report notes, however, that most investors approaching retirement are still struggling to sustain reliable retirement income. Of the nearly 25 million U.S. heads of households ages 50-59, about 21 million have accumulated less than $500,000 in investable assets.

"While these individuals generally have several years to continue adding to their retirement assets, they face an uphill struggle, especially considering widespread expectations of challenging equity returns and expected interest rate increases," the report states. "Frankly, even those who accumulate $1 million in retirement assets will likely be underwhelmed by generally accepted guidelines of only expecting $40,000 to $50,000 in annual income on such an asset base."