In June the West Brom narrowly avoided being broken up by reaching an agreement with its debt-holders by converting £182.5m of debt into capital.
College Hill was initially brought in to help the institution through that period and has now been given a retained communications brief.
The agency's financial team will advise the building society's board and in-house comms team on issues including results announcements and ongoing communications around the new management's 'back to basics' strategy.
Tony Friend, College Hill partner, said: ‘In common with many financial institutions, West Brom has gone through a difficult time; we are proud to have played our part in ensuring the Society continues to serve its loyal depositor base as an independent mutual.'
Sarah Hemmings, head of communications at West Bromwich, said: 'We greatly appreciated the hands on approach the College Hill team provided during testing times [and] look forward to their continuing support as our management team take the Society forwards.'