BEIJING -- Mergers and acquisitions by Chinese enterprises surged 37 percent year on year in 2012 in terms of their disclosed transaction value, according a report issued by a research and consulting institute.

The total value of disclosed M&A transactions involving Chinese firms amounted to $307.79 billion in 2012, up 37 percent year-on-year, according to data released Sunday by ChinaVenture.

The amount is the greatest recorded since 2007, with the total transaction value nearly tripling since then, the report said.

However, the total number of M&As was down last year, with a total of 3,555 transactions announced, down 23 percent from 2011, the report said.

The total value of completed transactions also shrank by 17 percent year on year to stand at $127.45 billion, the report said.

ChinaVenture analyst Fiona Wan said last year's M&As were marked by single transactions that involved large corporations and huge sums, resulting in fewer cases but a larger total scale.

Among the 2,458 closed M&As, a total of 230 were cross-border deals, generating a transaction volume of $36.63 billion, the report said.

Affected by the lackluster global economy, many overseas assets tended to be undervalued and Chinese investors were more willing to engage in mergers, Wan said.

The energy and mining sectors accounted for most of last year's M&A activity, topping other industries with a total transaction scale of $33.52 billion, according to the report.

A notable case was the China National Offshore Oil Corporation's bid to buy the Canada-based Nexen Inc for $15.1 billion, a deal that will be China's biggest overseas acquisition ever once completed.

In terms of the number of transactions completed, the manufacturing sector ranked first with 450 M&A deals closed in 2012, followed by the energy, mining and financial sectors, the report said.

The entertainment, cultural and Internet sectors also closed some major deals, including a $7.1 billion share repurchase by the Alibaba Group, a Chinese e-commerce platform provider, and Dalian Wanda Group Co's purchase of US cinema chain AMC Entertainment Inc.