U.K. alcoholic beverages company Diageo PLC said Monday that Chairman Vijay Mallya has said he won't resign, following a call to do so from United Spirits Ltd. over alleged irregularities in company accounts. Board members of United Spirits, which is majority-owned by Diageo, asked Mr. Mallya to step down as chairman over the weekend, after a PricewaterhouseCoopers inquiry into the company's books allegedly found "improprieties and violations," according to a person familiar with the matter.