Morgan, Lewis & Bockius LLP is an American multinational law firm with approximately 2,200 legal professionals in 31 offices across North America, Europe, Asia, and the Middle East. Mergers with other law firms stimulated global growth and led to a ranking of eighth on American Lawyer's 2018 top 100 firms by gross revenue list. It is also the largest law firm chaired by a woman, and represents "three-quarters of the Fortune 100 companies." The firm has served as tax Counsel to former US President Donald Trump, and the Trump Organization, since 2005. Morgan Lewis is known for high-profile pro bono representations and for filing a historic amicus brief in the US Supreme Court in 2015 on behalf of 379 companies, stating a business case for legalizing same-sex marriage across the country.