Weeks after Armand Wahyudi Hartono became the Vice-President Director of Indonesia's largest non-state bank, PT Bank Central Asia, he noticed how staff were leaving half-empty glasses of water after work. The next day, he restricted the amount of drinking water available at PT Bank Central Asia's headquarters.

What may seem as a step to save environment and natural resources is basically nothing but a stringent step towards cost control. According to reports, the focus on curbing in costs has been central to BCA's strategy.

In addition to water limits, it has imposed an Internet quota for its entire staff and even senior employees are subject to the restrictions. And meeting rooms don't come for free: Departments have to pay to use them.

“Indonesians are getting richer at a much faster pace than what the headline suggests, and they are also getting smarter and they save more money,” according to Taye Shim, director of capital markets at PT Mirae Asset Sekuritas Indonesia. “The country’s underbanked profile will continue to promise steady growth over the longer horizon, and BCA is the kind of bank that is preferred by the smarter and richer Indonesians.”

Bharat Joshi, Jakarta-based investment director for Aberdeen Standard Investment Indonesia, which owns more than 170 million BCA shares in media, "The high valuation of BCA is warranted as the company is a good defensive holding, especially in times of volatility," He further said that he like the bank for many reasons, but among all is its strong management capabilities and proven track record.