Indonesia might seem like a natural fit to join an expanded BRICS, the group of emerging economies made up of Brazil, Russia, India, China and South Africa.

The Southeast Asian nation of more than 270 million people is a major emerging economy that by some estimates could rank among the world’s top five economies by the middle of the century.

But when South Africa’s Cyril Ramaphosa announced the expanded BRICS membership in Johannesburg last week, Indonesia was not on the list, which includes Argentina, Egypt, Ethiopia, Iran, Saudi Arabia and the United Arab Emirates.

Indonesia’s decision to stay out of BRICS despite its similarities with other emerging economies reflects longstanding wariness of being entangled in geopolitical alliances as well as uncertainty about the economic benefits membership would bring, analysts say.