Citi is one of the world’s largest financial institutions, its Services business operates in 95 countries, over $5 trillion in transaction value every single day — much of it in real time, and nearly all of it dependent on the accuracy, lineage, security, and reliability of data.

With a 200-year legacy and thousands of systems across markets, banking, treasury, and securities services, Citi’s global operations run on millions of daily data exchanges. Every payment, liquidity decision, custody instruction, or trade settlement is essentially a data event.

To unpack how Citi is approaching this challenge, Harrison Williams, Head of Data Platforms, Standards, Governance & Analytics at Citi Services, sits down with Phil Andriyevsky, Financial Services AI and Data Leader at EY, for a candid discussion on what modernization really looks like inside one of the world’s most complex financial enterprises.

Why data is a priority

Williams begins with the scale of Citi’s Services’ operations: “Citi moves $5 trillion worth of money a day. That’s all ones and zeros running over a wire. We’re moving information.”

According to Williams, payments, liquidity, custody, broker services, etc., are all data-centric businesses. The act of the transaction itself is a data update. With nearly two centuries of accumulated systems and 100+ years of point-to-point integrations, the data estate had grown large, fragmented, and expensive to govern manually.

Modernization, Williams says, wasn’t about chasing a buzzword. “I recognize it’s a buzzword, but it’s very real for us. We have to manage our data correctly. As your estate grows, this cannot be a manual type of activity.”

Citi Services needed to:

• Map the physical nature of its global data estate
• Understand where the highest-value data lived
• Replace bespoke, point to point feeds with target state publishing patterns
• Reduce the total cost of ownership
• Strengthen governance and compliance
• Enable the business with cleaner, more accessible data

Only then could the organization align modernization to real client and business needs.

Defining modernization at Citi

Williams makes it clear that modernization is not a tooling exercise. Instead, it is a strategic, business-aligned transformation. The forcing event came from recognizing that legacy architecture, fragmented responsibilities, and manual governance could no longer scale.

Citi Services’ modernization needed to solve:

• High manual overhead
• Lack of consistent metadata
• Slow time-to-market for cross-border and new products
• Growing regulatory expectations
• The need for real-time observability

This meant both new technology and new responsibilities for people.

“We had to invest in our people too. When you move responsibilities upstream or downstream, you’re asking cohorts to work differently. They need the tools and training to evolve with us,” Williams explains.

A modernized Citi Services meant:

• More people can safely work with data
• Responsibilities are explicit
• There is less manual routing of requests
• Producers provide richer documentation
• Governance shifts left
• Consumers get faster, cleaner access

How Citi Services prioritized: Strategy, Period

Williams highlights a common pitfall among data organizations: creating a data strategy that only data practitioners understand. “I’ve seen people carry a brilliant data strategy into seniors’ offices focused on data-quality dimensions. That never goes over well.” Instead, Citi grounded its strategy in business pain points.

The prioritization process involved:

• Business-by-business interviews
• Mapping where data was “holding them back”
• Surfacing issues slowing growth or creating manual overhead
• Identifying cross-cutting themes
• Repeating these discussions throughout the year
• Aligning improvements with measurable business outcomes

This created dual ownership: “I get to say, ‘Here’s the platform that makes it more efficient and cheaper to manage data.’ And the business gets to say, ‘Here’s how this helps our product grow.’”

This joint narrative accelerated buy-in and funding. “Alignment around a shared strategy is the most important thing. It’s not data for data’s sake; it’s data to empower our businesses and our client needs,” Williams elaborates.

Why Citi’s story matters to other data leaders

Citi’s scale makes it a bellwether for financial institutions facing similar modernization challenges. The lessons are widely applicable:

• Modernization starts with understanding reality, not theory.
• Operating models must evolve or technology won’t scale.
• Self-service requires standards, governance, and automation.
• Strategy must be written in the language of the business.
• Cross-functional prioritization creates real alignment.
• Modernization is as much about people as platforms.

In William’s words, Citi Services is not modernizing for modernization’s sake. The Services business is modernizing to simplify global operations, strengthen governance, reduce cost, and position data as a competitive advantage across payments, liquidity, custody, and global markets.

CDO Magazine appreciates Harrison Williams for sharing his insights with our global community.