Citigroup has slashed the size of its struggling off-balance-sheet investment funds by more than $15bn in two months through quiet side deals with some junior investors, according to people familiar with the business.

The news that the troubled US bank has been finding ways to offload assets from its structured investment vehicles (SIVs) without resorting to fire sales comes as Société Générale on Monday became the latest bank to announce a bail-out for its own $4.3bn vehicle. SocGen’s decision follows similar moves by HSBC, Standard Chartered and Rabobank in the past fortnight.