Willis Group Holdings plc is a multinational risk advisor, insurance brokerage and reinsurance brokerage company with its headquarters in the Willis Building in London. It is the world's fourth-largest insurance broker when measured by revenues. Willis has around 400 offices in 120 countries and approximately 18,000 employees. Willis was previously listed on the New York Stock Exchange before its early-2016 'merger of equals' with Towers Watson. After the deal closed, the combined company began trading on the Nasdaq exchange under the symbol, WLTW (Nasdaq: WLTW)