Tesco is exploring the sale of its South Korean operations, valued at around $6bn, and has hired HSBC as a financial adviser, according to sources cited by Reuters.The potential sale of the South Korean operations - the company's biggest business outside of the UK - comes after Tesco unveiled in April its worst ever annual loss of £6.38bn.Tesco was also hit by an accounting scandal and several ratings downgrades.Tesco has received interest in the past for its South Korean operations, which has encouraged the company to explore a formal sale process, Reuters cited people close to the matter as saying.In February of this year, Tesco was approached by Thai billionaire Dhanin Chearavanont with an offer to buy its Thai operations, Tesco Lotus.At 1445 BST, the shares were up 0.6% at 211.75p, reversing earlier losses.