27th February, 2026|Zak Jakubowski

The asset manager has mandated Citi Investor Services to deliver selected middle office functions for $4 trillion (£3trn) in US domiciled iShares exchange traded funds operating on the Aladdin platform.
The partnership, announced on Friday, integrates Citi into core operational workflows across the iShares range, supporting order processing, basket transparency and settlement oversight. Assets under management in the relevant US domiciled ETFs totalled $4 trillion as at 31 January 2026.
Derek Stein, head of technology and operations at BlackRock, said the decision reflects confidence in Citi’s ability to meet the scale and governance requirements of the platform.
“Citi has been a trusted partner as we evolve our ETF operating model on Aladdin,” Stein said. “This appointment reflects our confidence in Citi’s ability to support the scale, transparency and operational rigour required across the iShares platform, ensuring efficient and resilient ETF operations for our clients.”
According to the firms, the integrated operating model is intended to streamline the lifecycle of ETF orders and provide enhanced visibility into basket composition and trade status.
The mandate builds on a prior agreement in 2021, when BlackRock appointed Citi as an additional post-trade service provider for its US domiciled iShares ETFs. Under that arrangement, Citi provides custodial, fund administration and transfer agency services.
Chris Cox, head of investor services at Citi, said expanding ETF and middle office servicing capabilities is central to the bank’s ambitions to increase market share with global asset managers.
“This latest collaboration with BlackRock reflects the outcome of our product and technology investments and deepens our relationship with a valued partner of the firm,” Cox said. “The success of our efforts to redefine a future state operating model for ETF middle office is a testament to our shared commitment towards building innovative industry solutions and delivering exceptional service to clients.”
Citigroup also made a strategic AI investment in Japan earlier this week.
In November last year BlackRock's Aladdin announced integration with AccessFintech to accelerate post-trade efficiency.