"It may be too late to invest new money"

CNBC's Jim Cramer said on Monday that it was difficult to place new sums in stocks even as the market posted gains.

The Dow Jones Industrial Average rose by more than 78 points on Monday, the S & P 500 index rose 0.47% and the Nasdaq composite index of 1.05%.

Cramer said investors should beware of moss, when stocks on fire soar for no apparent reason.

"We still have enough moorings so that I do not want to declare this market unmanageable," said the animator of "Mad Money." "We are not there yet, we are still too close to the fainting May, but I think it's probably too late to put new money to work without further respite or at least a new test of where we were at the beginning of last week. "

Beyond Meat, which issued a quarterly report higher than expected last Thursday, saw its stock increase another 21% Monday. That's after the badet jumped nearly 40% on Friday.

Cramer called the fake meat maker a "fantastic company", but said the stock's trajectory was "terrifying".

Beyond Meat added $ 3 billion to its market capitalization in just two days, thanks to the panic of short sellers – who bet the price of a stock will go down – desperate to trade stocks, and to "true believers" "who buy every stock can find," says Cramer. The nearly $ 30 rise in Monday's action was "fully focused on market mechanics," he said.

"In these situations, people do not care about why something goes up, they just want to have a winner," he said. "When you see people cramming into actions just because they're going up, that's what I call a bad sign."

The cloud sector has also had a hectic day, Cramer said.

Salesforce announced the acquisition of Big Data, Tableau, for $ 15.3 billion. While Salesforce saw its stock sink by more than 5%, a number of stocks in the cloud, such as Adobe (0.8%), VMWare (1.64%), Workday (1.05%) and Splunk (6.44%) surged, said Cramer.

"Stocks in the clouds are changing in the hope of getting a public takeover bid," he said. However, the aforementioned stocks are more likely to be buyers than sellers, "and that's why I think their stock will give up those gains."

Cramer suggested buying Salesforce shares in the weak because the stock may "recover maybe within seven days."

Amazon's gain of nearly $ 57 per share on zero news is another sign of "textbook foam," Cramer said.

The Cramer charitable trust owns Amazon shares, he said, but "we were tempted to sell some stocks simply because it was too hot, too fast".

Nevertheless, Cramer said that he was not convinced that the market was reaching a peak, which is why investors should keep at least a few holdings. For every stock that skyrockets, like Beyond Meat, there is an Uber or Lyft that hurt after being made public, he said.

Take United Technologies, which has agreed to acquire Raytheon under a full equity contract. The latter also saw its price drop by more than 4%.

"A really sparkling market would not punish Salesforce and United Technologies in this way," he said.

Disclosure: The Cramer Charitable Trust owns shares in Salesforce.com and Amazon.com.