Citigroup's (C) cost for renovating its office building in London has reached $1.5 billion, Reuters reported Sunday citing a company executive.

The bill is approaching the 1.2 billion pounds ($1.63 billion) it cost the US bank to acquire the tower in 2019, according to the report.

The budget was increased to accommodate a larger workforce and upgrade additional space, Reuters reported, adding that the project is expected to be completed next year.

Citi did not immediately respond to MT Newswires' request for comment.

(Market Chatter news is derived from conversations with market professionals globally. This information is believed to be from reliable sources but may include rumor and speculation. Accuracy is not guaranteed.)