Global merger & acquisition (M&A) activity has reached fever pitch this year, matching levels not seen since 2008. One analyst told CNBC he was concerned that the surge could indicate that bubbles are forming in the market.

According to data provider Dealogic, global M&A volume reached $804.5 billion in the first quarter of 2014, up 23 percent on the same period a year before, marking the highest level for the first quarter since 2008.

"M&A is getting a little crazy now. The first three months of this year we've had the highest M&A since 2008. Now does anyone remember what happened in 2008, wasn't there some kind of a global crisis? When you reach a peak in M&A it's usually a peak in the stock market," said Bert Dohmen, president and founder of Los Angeles-based Dohmen Capital Research Institute.

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In a separate report, Dealogic found that hostile merger and acquisition (M&A) activity around the globe has reached a seven-year high, at levels not seen since before the global financial crash of 2008.



Hostile takeovers occur when an acquiring company does not strike an agreement with the target company's management, instead going directly to shareholders with a deal, or replacing management.



Year-to-date hostile activity stands at $273.4 billion, according to Dealogic. Last year's figure for the same year-to-date period stood at just $70.6 billion. This year's performance so far looks to be the highest since 2007's figure of $377.4 billion.

M&A megadeals

The data come after a number of high-profile M&A megadeals in 2014. This week, headlines focused on U.K. pharmaceutical AstraZeneca's rejection of a revised £69 billion ($116 billion) acquisition bid from rival Pfizer.

On Monday, AstraZeneca said the U.S. company's "final" offer was inadequate and would present significant risks for shareholders, however, some shareholders have expressed disapproval of the deal rejection.

AstraZeneca Chair: Shareholders can 'vote me away'

Meanwhile, in the U.S., multinational communications corporation AT&T proposed to buy satellite TV provider DirecTV for $48.5 billion.

Other bumper deals that have hit the headlines this year include Facebook's $19 billion acquisition of WhatsApp in February, while in Europe a deal between GlaxoSmithKline and Novartis involved trading 11 billion pounds worth of assets ($18.5 billion).

But Dohmen warned that there are worrying parallels between the recent surge in M&A activity and the similar build-ups seen in 1999-2000, and in 2007-2008, which preceded market crashes.

"It's too exuberant. When companies have too much cash, they do not spend it wisely. Companies don't care about value anymore, all they care about making is deals," he added.

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Furthermore, Dohmen warned that the frenzied pace of M&A activity this year is an indicator of bubbles in the economy. He highlighted stretched valuations on the - a U.S. index consisting of small-cap stocks - where the price to earnings ratio is an average of 73, he said, compared to the Nasdaq's 35 and the 17.