South Korea's KB Financial Group (105560.KS) (KB.N) swung to a loss in the fourth quarter, hit by charges for the biggest-ever job cuts at its Kookmin Bank unit, the country's top lender.

KB posted a net loss of 231 billion won ($208 million) in the October-December period, versus a net profit of 17.8 billion won a year earlier.

The loss compared with an average forecast for a 242.6 billion won loss from 17 analysts in Thomson Reuters I/B/E/S. StarMine SmartEstimate, which places more weight on recent forecasts by top-rated analysts, forecast a higher loss at 274.4 billion won.

KB is cutting 12 percent of staff at Kookmin and spinning off the bank's credit card unit to focus on its core lending business as it faces steepening competition, with smaller rival Hana Financial Group (086790.KS) taking over Korea Exchange Bank (004940.KS).

KB said its loan-loss provisioning fell to 553 billion won from 685 billion won in the prior quarter.

(Reporting by Ju-min Park; Editing by Muralikumar Anantharaman and Jonathan Hopfner)