South Korea's anti-trust watchdog is probing local brokerages on suspicion of collusion in fixing the rates for the 91-day certificate of deposit (CD), local media reported Tuesday.

According to local securities firms cited by several media, the Fair Trade Commission (FTC) confiscated computers with records of quotation from 10 local brokerages that quote the CD rates and has been investigating officials concerned.

The CD rate, which is widely used as a benchmark for lending rates and some derivative products, is published by the Korea Financial Investment Association (KFIA) twice a day after excluding the highest and lowest rates from the rates offered by 10 securities firms.

The investigation came after the CD rates stayed at a high level despite the fall in other market rates. "The FTC is examining officials about why the CD rate has not moved and whether brokerages have been in collusion in setting the rates," an official at a local brokerage was quoted as saying in an interview with local media edaily.

The 91-day CD rate was quoted at 3.25 percent on Monday, while the three-year Korea Treasury Bond (KTB) yield finished at 2.95 percent. The three-year KTB yield plunged around 20 basis points ( bps) right after the Bank of Korea (BOK) unexpectedly cut its policy rate by 25 bps to 3 percent last Thursday.

South Korea's rate-fixing probe came as the global financial market was shocked by the Barclays' rate-rigging scandal.

Barclays, the third-largest bank in Britain, was fined a combined 452 million U.S. dollars by both U.S. and British regulators on June 27 for some of its traders and senior managers attempting to manipulate Libor, an important interbank lending rate guiding price-setting of financial products around the world.