Today’s gains in the S&P 500 completed the fifth recovery this year from a decline of 4 percent or more, just 17 days after it started. In comparable drops beginning in January, April, July and September, the S&P 500 needed about a month to erase losses, data compiled by Bloomberg show.

This is the 50th time this year the S&P 500 has closed at an all-time high, while the Dow has done it 35 times. The S&P 500 reached records on 45 occasions in 2013, as the index recovered from the financial crisis to top its previous high from October 2007 for the first time.

The latest rebound gives the S&P 500 a gain of 5.4 percent for the month so far. The index has advanced in each of the past six Decembers, climbing an average 2.2 percent.

U.S. equities jumped 5.4 percent in the past four sessions, the best performance over that stretch since 2011, as Fed Chair Janet Yellen said the central bank will likely hold key rates near zero at least through the first quarter, even as the U.S. economy strengthens. Yellen also said any spillover from the situation in Russia is likely to be small.

U.S. stocks have tripled during the 5 1/2-year bull market, driven by the Fed’s three rounds of bond buying and borrowing costs near zero to stimulate the economy.

David Fuller's view

“Bull markets are born on pessimism, grown on skepticism, mature on optimism, and die on eurphoria.”

Sir John Templeton

Where do you think we are in this cycle described by Sir John?

Starting with the S&P 500, I would say we are in the mature on optimism stage.  However, sentiment towards most other diversified stock markets is somewhere between pessimism and scepticism, I suggest.  This is also reflected by valuations.