"The 400 point drop we're about to have!" -- Rick A., California
"First, traders will take out profits and move the money to more aggressive markets - Asian interest. The worldwide geo-political events can not be over looked and the Middle East can have the biggest impact on the markets. There is a growing concern about the ability to sustain growth of revenues and consumer confidence - this will take the markets down. And then there are the Hedge Funds." -- Bob P., Florida
"Inflation fears in China, Great Britain, and Europe will bring about the end of the rally but not for a while yet." -- Mike S., New York
"The high cost of gas. I live on Long Island and am now paying 306.9 for a gallon of regular gas and the driving season is not even here yet. I'm a baby boomer, and most of my friends are starting to cut back on major purchases. In the last 6 months I understand that the foreclosure rate on Long Island is 15% and going higher." -- Al R., New York
"The lack of equity in housing is going to slow consumer spending." -- Fernando A., Florida
"Apologies if this sounds too wordy and theoretical, but nobody can predict with certainty what the core cause is in a plunge. In their book 'Nonlinearly, Chaos & Complexity (The Dynamics of Natural and Social Systems)' by Bertuglia & Vaio, they explain that the market
... The market is just too complex to focus on any one causal motion. It's more like a pool of waves, and you have to hope the perfect storm won't occur while you are out surfing. There are thousands of traders sitting at home putting and calling options, and whatever sentiments they put into the market feeds back and affects the very prices they are trying to predict. But since this question asks for likely: some events that could combine unfortunately for the bulls this summer could be 1.) A definitely Global Warming weather event, as in 'This has never happened before and it is horrible.' at the same time as 2.) Dollar dropping yet no company set to take advantage of maximizing global exports and 3.) A political, subsidy-tariff driven argument with a key world player just at the wrong time for reversing the trade deficit. Luckily, this is unlikely to happen in the same close time-frame." -- Ed L.
"I expect that the failure of one of these mega-mergers or LBO's to be consummated will be the catalyst (but not necessarily the cause) of the end of the market rally." Carl H., Massachusetts
"The realization of reality. That is, the reality that the country is bankrupt (public and private), fiscally and ethically." -- Debbie B.
"The bursting of the credit bubble we have been living in for the last 6 years." Art F.
"Hillary Clinton becomes the front runner for President. Terrorist attack. The Fed Tightens in 2007. Poor earnings report from the Retailers. A bankruptcy/Chapter 11 announcement with a DOW stock. Mid-East major leadership change." -- Mike A.
"Fed interference." -- Frank M.
"Simply put...our marginally elected “Congress” is most likely to derail the stock market rally." -- B. Short, Florida
"Some democrat." -- Joe P., Florida
"The month of May." -- Ray P., Florida
"What's most likely to derail the stock market rally? DEMOCRATS!" -- Ray M., Florida
"I think there is a lot of money to invest due to the housing market not being a viable choice for investors. Just as when the housing market was hot, the market was impacted." --Maureen M., Arizona
"Economic data that shows growth is abating too much and followed by poor Q1 & Q2 earnings results. There is always the ever present global event risk factor that could shake up the market. Things are not that bad and the equity markets are reflecting just that. Perhaps the Fed has finally found the perfect balance at FF rate of 5.25%. Data has continually come in mixed of late which may be the indication that we have achieved balanced growth and pricing stability. I remain data dependent along with the Fed." -- Ann M., Florida