Stocks rising, bulls rampant are motifs you might pick if designing a coat of arms for Wall Street at the moment. But the motto should read: Caveat emptor. Yes, buyer beware.

The S&P 500, a broad measure of the market valuation of the biggest U.S. publicly traded companies, is up 20 percent from its October closing low. It keeps climbing on a mixed bag of fourth-quarter earnings, improving U.S. economic data, and easing credit conditions in Europe. It now stands at its highest level since early last August.

We have already seen what is probably the first upgrade of a target level for the index this year courtesy of Credit Suisse.

The CBOE Volatility Index, or VIX <.VIX>, a measure of what investors are paying to protect themselves against the risk of losses, is at its lowest level in seven months.

So it raises the question: Is this another Jackson Hole moment for risk assets?

At the Wyoming retreat in late August 2010, Federal Reserve Chairman Ben Bernanke sparked what was the second major leg of the stock market's rally from bear market lows the year before.

Is this the start of the third?

FRIENDLIER FOOTING FOR STOCKS

For Andrew Garthwaite, the Credit Suisse analyst behind the firm's more bullish stance, there are big changes afoot that are creating a more benign environment for stocks.

First, the European Central Bank's long-term repo operations are succeeding in reducing stresses in the region's banking sector. This week, three-month dollar Libor, the cost at which European banks can borrow dollars, marked its ninth straight day of declines.

Analysts say heavy cash infusions from the European Central Bank since late last year and signs of revived willingness to lend by U.S. investors in the new year show the banking system is flush with cash.

The U.S. economy is looking stronger than thought, with notable movement in the long-dormant housing market, where sales of previously owned homes just rose to an 11-month high.

In China, the engine of global growth whose manufacturing sector has been showing worrying signs of slowing, policymakers have demonstrated willingness to make conditions easier by lowering banks' reserve requirements.

As we approach our year-end target two weeks into January, we have to ask ourselves the following questions: What has changed? Will equities rally further?, Garthwaite said in a research note.

His answer to the second question was yes. Credit Suisse raised its year-end S&P 500 target to 1,400 from 1,340. Critically, however, the firm did not overweight equities, saying the risks of a more severe recession in Europe and a slowdown stateside were still there.

HEALTHY DOSE OF SKEPTICISM

For Nicholas Colas, chief market strategist at the ConvergEx Group in New York, the rally remains largely untested. More scary headlines from Europe or any signs that the global economy is deteriorating could spark a sharp reversal.

On Sunday, Greece's private creditors were working closely with the Greek government on a debt-swap deal, according to their chief negotiator, Charles Dallara, the head of the International Institute of Finance. Dallara told Antenna TV in Greece that he is confident that a deal can be reached. [ID:nL5E8CM0HB] Creditors faced losses of up to 70 percent of the loans they have given to Athens.

Most of the attention will now shift to a Monday meeting of euro-zone finance ministers, and to how EU states and the IMF view the progress in the debt-swap talks.

It's a confidence-based rally with the overhang of several still meaningful events to come, Colas said. It is all well and good to say that the Greek default is well understood, but we haven't gone through it.

Outside the United States, there are mixed signals from the global economy, too.

China's factory activity likely fell for a third successive month in January. The HSBC flash manufacturing purchasing managers index (PMI), the earliest indicator of China's industrial activity, stood below 50.

The Baltic Exchange's main sea freight index <.BADI>, which tracks rates to ship dry commodities and can be a useful gauge of economic activity, fell to its lowest level in three years on Friday on a growing surplus of vessels and a slump in cargo demand.

That is at odds with the work of RBC technical analyst Robert Sluymer. He sees growing outperformance of industrial metal copper to the safe-haven bet of gold as well as a rise in a basket of Asian currencies as a bullish sign for the economy.

The caution generated by the mismatches in the various data points is reflected by U.S. interest rates.

The yield on the U.S. 10-year Treasury note has hovered at 2 percent or just below for the last month despite a brief spike in mid-December. That suggests bondholders are not eagerly embracing the improving economy thesis for the moment.

There is still a lot of skepticism about recovery, about moving into risk assets, about a lot of things, Colas said.

If you really wanted to believe this about incrementally economic certainty and expansion ... I would have thought you'd expect to see the 10-year back over 2 percent.

EARNINGS, DATA AND THE FED

Monday will start one of the two most hectic weeks of the earnings season. Big names on Monday's earnings roster include Texas Instruments Inc and Halliburton Co .

The blitz of earnings plus economic indicators and a Federal Reserve meeting will give Wall Street an important gauge of the economy's health - and the outlook for interest rates.

On Tuesday, the Federal Reserve's policymakers will convene their first meeting of the year with a two-day session. The Federal Open Market Committee, the Fed's rate-setting panel, will release its policy statement on Wednesday. No fireworks are expected, but a decision to release individual policymakers' interest-rate forecasts could alter expectations for rates on the margins.

This week's economic data will include December pending home sales data on Wednesday and a trio of reports on Thursday, when the latest weekly jobless claims, December durable goods orders and new home sales for December will be released. Friday will bring the government's first look at fourth-quarter U.S. gross domestic product and the final January reading on consumer sentiment from Reuters and the University of Michigan.

But Wall Street is most likely to be preoccupied with earnings. Tuesday's agenda calls for quarterly results from Apple Inc , DuPont, Johnson & Johnson , McDonald's Corp and Yahoo! Inc .

Boeing , ConocoPhillips and United Technologies are set to report results on Wednesday. Thursday's earnings line-up includes 3M Co , AT&T Inc and Starbucks . On Friday, Chevron Corp and Procter & Gamble Co.

will weigh in with results.

In terms of companies beating expectations, the fourth-quarter earnings season has not been as good as previous ones. Of the approximately 70 companies in the S&P 500 that have reported earnings so far, 60 percent have exceeded analysts' estimates, according to Thomson Reuters data.

In comparison, in the third quarter at this early point in the reporting cycle, 68 percent had beaten Wall Street's forecasts -- well below the 78 percent in that category in the second quarter, Thomson Reuters data showed.

In the earnings season so far, there have been some high-profile misses on both revenue and earnings.

General Electric Co's fourth-quarter revenue fell short of Wall Street's expectations, with Europe's weakening economy and weak appliance sales the main culprits.

On the other hand, banks' earnings have served as a positive catalyst for the stock market so far. The sector has been one of the market's leaders despite mixed earnings, a sign that investors' worst fears did not materialize.

(Reporting By Edward Krudy; Editing by Jan Paschal)