Lotte Group, South Korea's fifth-largest conglomerate, was the most active among local business groups in using mergers and acquisitions to diversify its business over the past five years, data showed Monday.

Among 592 companies affiliated with the nation's top 10 business groups, 98 firms, or 16.6 percent, have been added through M&As since 2010, according to Chaebul.com, a website that tracks the nation's large enterprises.

The number of newly acquired companies increased from 5 in 2013 to 14 last year. So far this year, 19 companies have been bought by the family-run conglomerates, called chaebol here, which wield enormous power over the national economy.

Lotte Group has purchased 19 firms, including a convenient store chain and an electronic goods retailer, over the past five years to beef up its retail and food business. 

Hyundai Motor Group, the world's fifth-largest automotive group, has acquired 13 companies, including an engineering unit and a construction company. The number of affiliates that have joined the automaker since 2010 accounts for 26 percent of its total subsidiaries.

While cash-rich chaebol have used M&As as a convenient way to expand their sprawling business empires, market watchers stressed the industry leaders' efforts to foster new growth drivers to revitalize Asia's fourth-largest economy.

"Acquiring companies that have already been verified does not help foster the market in a creative way," said Chung Sun-sup, CEO of Chaebul.com. "It is not appropriate for chaebol to expand their businesses by excessively relying on M&As under the name of business diversification." (Yonhap)