Both could be sold to help City comply with UEFA's financial fair play rules.
Bony could be a replacement for Swans striker Fernando Llorente, according to Dafydd Pritchard of BBC Wales Sport. Yet the report also noted how Besiktas are interested, with the Ivorian's wage demands unlikely to put the Turkish champions off: "Bony is believed to earn more than £120,000 a week at City but, having qualified for the Champions League, Besiktas have money to spend."
It's no surprise Bony's career with the Citizens appears to be coming to an end. The attacker, whose contract expires in 2019, has scored just eight goals in 46 appearances, per Pritchard.
Bony swapped Swansea for Manchester in 2015 but couldn't make the grade at his new club. His pace, prowess in the air and intelligent hold-up play can still be assets in the right squad, though.
This isn't the first time Bony has been linked with a return to the Swans. Earlier this month, another report from Pritchard revealed the Welsh club was considering bringing the 28-year-old Ivory Coast frontman back.
Bony is far from the only player who failed to deliver after sealing an expensive transfer to the Etihad Stadium. City could also ship out former FC Porto defender Mangala.
The Frenchman is wanted on loan by Juve, per Paul Hetherington of the Daily Star Sunday: "They have made contact with the agents of Mangala, who is available at the Etihad. City want £18 million, but Juventus would prefer a loan with a view to buying next year."
Hetherington revealed City could warm to the approach from Juventus, provided the fee is right: "That could be acceptable to City, if last season's Champions League finalists pay £4 million as a deposit with the balance to follow next summer."
Signed by City for around £32 million in 2014, Mangala has struggled in the Premier League. A move elsewhere seems inevitable for the player who spent last season on loan at Valencia.
Mangala has already rejected advances from Russian side Spartak Moscow, according to James Ducker of the Daily Telegraph. Meanwhile, Hetherington named Lyon and Los Che as potential suitors for the centre-back.
Ducker pointed out how City need to trim the squad after spending £220 million on new faces already this summer, including full-backs Kyle Walker and Benjamin Mendy.
The spree has alerted UEFA, who are concerned about violations of financial fair play rules, per Ducker: "City and Paris Saint-Germain were fined for breaching UEFA's financial fair play rules three years ago and the two clubs' activity in this summer’s window is now being scrutinised again."
Mangala and Bony are both identified as players City manager Pep Guardiola will look to sell during the remainder of this transfer window.
It makes sense for City to cash in on both Bony and Mangala. Neither has much, if any, chance of making the starting XI on Guardiola's watch, particularly following City's raft of signings this summer.