BOGOTA (Reuters) -Shareholders of Grupo Argos and Grupo SURA, two of Colombia's largest conglomerates, on Monday gave their boards the green light to begin studying alternative corporate structures in order to split the currently tightly-knit firms.

Argos and SURA are part of an alliance of firms known informally as Grupo Empresarial Antioqueno (GEA), made up of over a hundred firms held together by complex shareholding arrangements and partnerships.

These include lender Bancolombia, cement maker Cementos Argos, energy firm Celsia and pension fund Proteccion.

The firms' shareholders have voted for their boards to examine different possible structures without incurring a conflict of interest, according to an Argos statement and a source from SURA.

Argos currently holds a 45.8% stake in SURA, which in turn owns 45% of Argos.

Argos' CEO Jorge Mario Velasquez told shareholders during a meeting in Medellin that the firm had hired corporate financial advisors to study the possible alternatives.

"We do not have a strict time-frame as of today," Velasquez said. "This is going to take some time so that we are able to study the matter prudently and make a competent decision."

The examination of a new corporate structure follows forays by Grupo Gilinski - a rival alliance controlled by one of Colombia's richest men Jaime Gilinski - and its Arab partner, the International Holding Company (IHC).

Gilinski has launched a series of offers for shares in GEA firms, and in 2022 launched an failed tender offer for close to a third of Grupo Argos.

Last year, Grupo Gilinski secured a deal for a controlling stake in the country's largest food processing firm, Nutresa, in exchange for exiting its stake in SURA.

SURA's chairman Ricardo Jaramillo told shareholders it was time to present the board with alternatives to its current ownership structure, the source from SURA said.