Both Park Geun-hye and Shin Dong-bin, chairman of the retail giant, have denied the accusations that they were involved in exchanges of presidential favours for large sums of money.
South Korean prosecutors on Monday charged ousted president Park Geun-hye and Lotte Group chairman Shin Dong-bin with bribery in the latest twist to a corruption scandal that rocked the country for months.
Prosecutors charged Shin without detaining him.
Park was arrested on March 31. She has also been charged with abuse of power and coercion by pressuring big businesses to contribute funds to non-profit foundations, the prosecutors said.
The probe by prosecutors has already convulsed the biggest conglomerate, Samsung Group, with its chief Jay Y Lee under arrest for bribing Park and her friend, Choi Soon-sil. All three are being held at detention centres.
The retail giant Lotte, with interests ranging from hotels and retail to food and chemicals, becomes the second conglomerate mired in the political scandal.
Prosecutors accused Park of colluding with Choi to receive 7 billion won ($6.16 million) from Lotte for favours, they said in a statement.
Lotte denied allegations that it made improper deals with Park, or those linked to her, for favours, but said it would explain itself at court to resolve suspicions.
Lotte's chief Shin is also on a separate graft trial involving family members charged with embezzlement and breach of trust.
Park, Lee, Choi and Samsung Group have also denied wrongdoing.