Interconexión Eléctrica S.A. E.S.P.

What it is

ISA — formally Interconexión Eléctrica S.A. E.S.P. — is a Colombian company specialising in energy transmission, road concessions, and telecommunications infrastructure, and is the largest energy transmission company in Latin America, operating high-voltage networks in Colombia, Peru, Bolivia, Brazil, and Chile.

It operates 50,000 km of electricity transmission lines with a total capacity of 92,600 MVA, and these power-grid activities contribute 80% of the group’s total revenue. The company also designs, builds, operates, and maintains highway infrastructure, and was founded in 1967, based in Medellín, Colombia.

Who owns it

In August 2021, Ecopetrol — Colombia’s state oil company — closed a deal acquiring 51.4% of ISA’s shares, paying USD 3.58 billion for that controlling stake. Because the Colombian government controls Ecopetrol, ISA is ultimately state-owned — twice over.

The remaining ~48.6% is freely traded on the BVC and as American Depositary Receipts on the US OTCQX market. ISA registered its Level I ADR (ticker IESFY) with the US Securities and Exchange Commission in 2004.

Who runs it

At its board session of 29 April–4 May 2026, ISA’s board determined that Gabriel Jaime Melguizo Posada would cease to serve as interim chief executive, and designated Olga Patricia Castaño Díaz as the new interim president by unanimous vote.

Castaño Díaz had been vice-president of Strategy since 2014, has 26 years inside the company, holds a business degree from the Universidad de Antioquia and a master’s in operational research from the University of Lancaster. The outgoing board chair, Juan Pablo Zárate Perdomo, led the 2026 shareholder assembly that set the strategic path for the next two years.

The money, in plain words

In 2024, ISA posted the highest profit in its history: net earnings of COP 2.8 trillion (~USD 811 million), up 14% from 2023, on consolidated revenue of COP 15.8 trillion (~USD 4.6 billion), itself 12% higher than the prior year. It keeps roughly 18 cents of profit from every peso of sales — a net profit margin of ~17.7% (our calculation), strong for a regulated grid operator.

ISA delivered a return on average equity (ROAE) of 17%, the highest in five years — meaning for every peso shareholders have invested in the business, ISA earned about 17 centavos back in a single year. By end-2024, total financial debt stood at COP 34.5 trillion (~USD 10 billion), 11% more than a year earlier — hefty, as is normal for a company that builds and owns enormous infrastructure assets over decades.

What it is doing now

In 2024, ISA won new projects worth COP 3.8 trillion (~USD 859 million) and expanded into new geographies. For the next five years it has capital commitments already in hand exceeding COP 26 trillion (~USD 7.5 billion), providing clear visibility on future growth.

The company’s forward plan, called ISA2040, is designed to address the three core challenges of the energy transition: reliable supply, accessible service, and sustainability. The leadership picture, however, remains unsettled: Colombia’s Council of State annulled the appointment of Jorge Andrés Carrillo as president in a February 2026 ruling, finding that evaluation criteria had been materially altered mid-process.

What to watch

• Permanent CEO. ISA has now had three chief executives in quick succession; a definitive appointment will be the single most important governance signal for investors in 2026.
• Chile blackout liability. In February 2025, ISA was implicated in Chile’s nationwide blackout; regulatory sanctions and their financial cost are still being resolved.
• Debt load vs. growth pipeline. A financial-debt-to-equity ratio above 1.2x (our calculation from available data) is manageable given regulated, long-term revenues — but rising interest rates in the region increase refinancing costs each cycle.
• Ecopetrol’s own pressures. If Ecopetrol faces a period of lower oil prices and weaker earnings, ISA’s steady cash flows act as a buffer for the parent — but it also means ISA’s governance and dividend policy are never entirely insulated from its controlling shareholder’s needs.

This is news, not investment advice.