Forwards Haris Vuckic, midfielders Shane Ferguson and Gael Bigirimana, and defenders Kevin Mbabu and Remie Streete have all moved to Rangers on a temporary basis.
Vuckic and Ferguson are arguably the most high-profile moves, with both men having gained international experience with Slovenia and Northern Ireland respectively.
Newcastle owner Mike Ashley also has a stake in Rangers and it was recently reported the businessman had provided the financially-stricken club with a loan.
Meanwhile, Celtic announced they have secured midfielders Stuart Armstrong and Gary Mackay-Steven from Scottish Premiership rivals Dundee United.
Armstrong has signed a three-and-a-half year deal with the 22-year-old having scored six goals in 20 matches for Dundee United this season.
Mackay-Steven, 24, agreed to a four-and-a-half year contract after five goals in 21 games this term.
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