Westpac Says AI Halved the Cost of Moving St.George’s Data Warehouse to About $35 Million

Westpac says AI tools cut the cost of moving its legacy St.George data warehouse from a budgeted $70 million to around $35 million and allowed the work to finish more than two years ahead of schedule, iTnews reported on November 2. The figures appeared on a slide in the bank’s full-year results, an unusual spotlight for a back-office technology project.

Chief executive Anthony Miller said the team used AI to accelerate code conversion, testing and documentation, and presented the migration as an example of how the technology is helping deliver Unite, Westpac’s large simplification and transformation program. The bank first described the project at a digital, data and AI investor day in September, when it focused on the time saved; the results now put a dollar figure on it. Westpac expects about $15 million a year in direct benefits, which it will start booking from the 2027 financial year, when the old warehouse is due to be decommissioned. The data is moving to Adapt, the bank’s cloud data and analytics platform built on Microsoft Azure.

Miller also said the project had produced a reusable AI data migration capability, with tools, methods and experience that can be applied to other migrations, calling it a good example of what is possible when AI is built into programs of work. The results came as Westpac reported statutory net profit of $6.8 billion for the year to September 30, down 1% on the previous year.

What it means in practice

Legacy data migrations are among the most expensive and risky projects in banking, so a repeatable method could matter more than the one-off saving. Hard numbers like these remain rare in Australia, where Treasury has warned that shallow AI uptake risks the country’s productivity gains and banks and business groups have told Parliament’s AI inquiry to keep more AI value onshore. A disclosed saving of this size gives other institutions a benchmark for their own modernisation business cases.

What to watch is whether Westpac reports the realised benefits once the old warehouse is switched off, which systems it moves next with the same AI approach under Unite, and whether the other major banks publish comparable figures.