Jagannathan spoke to Computerworld UK at Oracle OpenWorld this week in San Francisco, where he was giving a talk on Citi's implementation of Oracle's Siebel CRM application.

Citi has 4,400 Siebel users, across 93 countries, and deals with 5 million analytic queries a month, as well as 300,000 deals and 60,000 call reports. Citi is currently using Siebel 8.1, but does upgrades every 24 months.

However, Jagannathan told Computerworld UK that due to increasing compliance concerns in the financial services industry, which vary in complexity across the globe, Oracle's public cloud is a no-go for Citi.

"Given the global nature of our business, combined with data privacy and regulation concerns, we are tied up quite a bit. Cloud is pretty challenging," he said.

"We did consider it, but because we store both customer and transactional data, it would be a challenge in several of the markets we operate in.