The valuation rose to a high of 13.8 from 7.3 during the first 15 months of the 1982 advance that pushed the S&P 500 up 229 percent, according to data compiled by Bloomberg. In the 1990s rally led by technology companies, it almost doubled to 28.5 during the eight years.

'Glum to Glee'

"As a country, we go from glum to glee and glum to glee over and over again," James Paulsen, the chief investment strategist at Minneapolis-based Wells Capital Management, which oversees about $325 billion, said in a phone interview. "After the 2008 recession and the tech bubble, we're back at glum, so what comes next?" he said. "Confidence, and the ability to rebuild it, is our biggest asset for the future."

Economists predict global GDP will increase 2.6 percent next year from 2.2 percent in 2012, the slowest since it contracted three years ago, according to a survey by Bloomberg. The pace of U.S. growth will be 2 percent in 2013, down from 2.2 percent this year, according to the median of 98 estimates.

The tumble since Obama defeated Republican candidate Mitt Romney, with 303 electoral votes to 206, pushed the benchmark gauge to 13.7 times reported profits, lower than the 15.5 average ratio since March 2009, according to data compiled by Bloomberg. Only one bull market since 1962 has ended with a lower valuation: the six-year cycle through 1980 in which the index gained 126 percent to 140.52, or 9.1 times profits.

Average Ratio

The ratio averaged 17.4 during the nine rallies and ended at about 19.9. Reaching the mean level would require a 26 percent gain in the S&P 500, holding earnings constant, data compiled by Bloomberg show. Should profits meet analysts' 2013 projection, the index would need a 42 percent gain from the Nov. 16 closing price. Earnings are forecast to climb to a record $110.80 a share next year, almost double what companies posted in 2008, analyst estimates compiled by Bloomberg show.

"Valuations are cheap given what we've seen in earnings," said Hank Smith, chief investment officer at Haverford Trust Co. in Radnor, Pennsylvania. His firm oversees $6.5 billion in assets. "Corporate America is strong, balance sheets are exceptionally strong and flush with cash. We do not believe we'll have a contraction in earnings next year. We expect profit growth to re-accelerate in the second half of 2013."

Apple Multiple

Apple, which has fallen 25 percent from its high of $702.10 on Sept. 19 traded at 11.9 times reported profits, a 14 percent discount to its five-year average, data compiled by Bloomberg show. The ratio reached a record 23.3 times income 2 1/2 years ago, even after the Cupertino, California-based company posted record earnings in the first quarter.