The number of Muslims is subject to significant controversy. Estimates range from 700 million to 1.2 billion worldwide and between 2 million and 7 million in the United States. The most often quoted estimate that there are between 6 and 7 million Muslims in America is based on the 2000 Mosque Study Project. The 6 to 7 million person estimate is for the total population; 2 million of those are associated with a mosque. The 2000 Mosque Study Project was commissioned by the Council on American-Islamic Relations (CAIR), the Islamic Society of North America (ISNA), the Ministry of Imam W. Deen Mohammed and Islamic Circle of North America. The questionnaire was given over the telephone to mosque leaders between March and September 2000.
 SwissInfo (October 9, 2006) cited Moody's Investors Service who estimated the Islamic finance industry at $750 billion worldwide. A Time Europe magazine article (December 16, 2002) placed assets held by Islamic Financial Institutions (IFIs) at $300 billion while a Business Week story (August 5, 2005) estimates IFI assets at $262 billion.
 The following banks offer Shari'ah-compliant banking (listed by state):
Minneapolis/St. Paul, Minnesota
New York City Area
* HSBC does not offer Islamic services within the U.S. but has an office in New York City
 The following investment companies operate or have offices in the U.S.:
 This estimate was provided in Business Week (August 8, 2005).