(Reuters) - U.S. Republican presidential candidate Ben Carson raised about $23 million in the last three months of 2015, Politico reported on Wednesday, citing his campaign manager.
Carson, a retired neurosurgeon, has fallen in recent weeks from second to fourth place in many national opinion polls and has said he plans a shake-up of his campaign staff.
As recently as November, Carson had challenged real-estate billionaire Donald Trump as the front-runner in national polls. He now trails Trump, Texas Senator Ted Cruz and Florida Senator Marco Rubio, according to a Real Clear Politics average of national polls.
(Writing by Eric Beech in Washington; Editing by Paul Tait)