LG Chem Ltd., South Korea's leading chemical company, said Thursday its second-quarter net profit plunged 91 percent from a year earlier on sharply decreased shareholding gains from battery unit.Net profit for the three months ended in June plummeted to 59.79 billion won (US$43 million) from 670.81 billion won in the same period of last year, the company said in a statement."The petrochemical business shifted to a profit in the second quarter (from a year ago), but sharply decreased equity gains from key affiliate LG Energy Solution dealt a blow to the bottom line," a company spokesperson said.LG Chem owns a 81.84 percent stake in LG Energy Solution, the country's biggest car battery maker by sales.Operating profit fell 34 percent to 405.86 billion won in the second quarter from 617.64 billion won a year ago. Sales were down 14 percent to 12.29 trillion won from 14.34 trillion won.Source: Yonhap News Agency