The Standard & Poor's 500 has had a long and storied relationship with a technical level it crossed Monday, but the affair always has ended in tears.
Over the past 13 years, the broad market index has crisscrossed 1350 on at least half a dozen occasions. But only once has it managed to keep going. The other times it eventually fell back.
The first time came all the way back in April 1999, the most recent occasion (after Monday) being July 2011 - a short-lived foray that preceded a summertime swoon from which the stock market only recovered this month.
With positive market sentiment at a fever pitch, investors could be setting themselves up for another 1350 fail.
"The rally since October 2011...has been impressive considering the lack of any real resolution to the European financial crisis and a sluggish U.S. economic recovery. It's been a very pleasant 'risk-on' journey for over four months," Nicholas Colas, chief market strategist at ConvergEx in New York, said in a note.
"But as hale and hearty as risk may appear to be, we have to remember that we've seen this movie before," he added.
The S&P 500's (INDEX: ^GSPC - News) journey with 1350 reads like a diary of market glee and despair.
The first cross came as the Internet bubble was in full swing, the second a year later just before it popped. Stocks soared past 1350 in October 2006, and a year later the index hit its historic peak at about 1560.
Of course, we know what happened from there: The popping of the housing bubble, the collapse of an army of Wall Street titans, and the intraday "devil's" low of 666 in March 2009. In between, the index criss-crossed 1350 on several occasions, never able to hold its ground.
Market spirits have been riding high in this latest run to 1350 - the highest, in fact, since January 2011, according to the American Association of Individual Investors survey. Meanwhile, short interest, or investors betting against stocks, at the New Stock Exchange is at its lowest since those dour days of March 2009.
"Investors are positioned for a continuation of the recent risk rally," Bank of America Merrill Lynch said in a note. "Investors' assessment of their own risk levels also suggests that there is more room for further risk rally."
In a technical analysis, the firm considered a successful test of 1336 to be significant and believes there is a clear path to 1370 or 1375.
The most recent BofA Global Investment Survey indicates 20 percent with risk "full on" in their portfolios, while 55 percent say they are at "average" levels. Just 20 percent are "below average."
That's cause for concern, though, on two levels: Such inflated optimism often precedes market downturns, and the enthusiasm isn't shared on the corporate level. Insiders have sold $2.3 billion in shares for February, more than 15 times the $145 million they've bought, according to market research firm TrimTabs.
That trend also has been reflected in share buybacks, which have dropped off as well to $1.7 billion a day, the lowest level in a year and a half.
"The bulls do not seem to have noticed that U.S. companies are committing less of their own money to buy shares," TrimTabs CEO Charles Biderman said. "The slowdown in buybacks is worrisome because our research shows buyback volume is highly correlated with stock prices."
Biderman believes the only real reason to buy stocks in this environment is on belief that the Federal Reserve will go an another bond-buying spree, known as quantitative easing . Even then, he said, stocks face a difficult road.
"The most strongly held conventional wisdom on Wall Street is that central banks can ride to the rescue in any financial crisis by printing more money without any real negative consequences," he said. "We think Wall Street's faith in central bankers is badly misplaced, and we think their constant market manipulation will end in disaster."
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