Question: Where is the group which  Stephen Martin  as the chief executive officer based?

Context articles: Jonathan G. Ornstein
Bobby Mehta
Stephen Martin (businessman)
Clugston Group
Khaled Bichara
Mike Lunsford
B. Wayne Hughes
Charles Bunch
Glen Post
Stephen Wolf

Jonathan Ornstein is Chairman and Chief Executive Officer of Mesa Air Group, Inc., and was appointed effective May 1, 1998.
 From April 1996 to his joining the company as Chief Executive Officer, Ornstein served as President and Chief Executive Officer and Chairman of Virgin Express, a European airline.
 From 1995 to April 1996, Ornstein served as Chief Executive Officer of Virgin Express Holdings, Inc.
 Ornstein joined Continental Express as President and Chief Executive Officer in July 1994 and, in November 1994, was named Senior Vice President, Airport Services at Continental Airlines.
 Ornstein was previously employed by the company from 1988 to 1994, as Executive Vice President and as President of the company’s WestAir Holding, Inc., subsidiary.
Siddharth N. "Bobby" Mehta was former CEO and vice chairman of HSBC North America.
 Mehta served as an Advisor of TransUnion since December 31, 2012.
 Mehta serves as consultant of TransUnion.
 He served the chief executive officer and president of TransUnion from August 2007 to December 31, 2012, and Transunion Financing Corp. until December 31, 2012.
 From May 2007 to July 2007, he served as a consultant to the board of directors at TransUnion.
 He served as the chief executive officer and president of TransUnion until December 31, 2012.
 He served as the chief executive officer of TransUnion LLC.
 He served as chairman of the board and chief executive officer of HSBC Finance Corporation from April 2005 to February 2007.
 He served as chief executive officer and president of TransUnion LLC from 2007 to 2012.
 From 1998 to 2007, he held a variety of positions with HSBC Finance Corporation and HSBC North America Holdings, Inc.
 Mehta served as chief executive officer of HSBC North America until February 2007.
 Mehta served as consultant of TransUnion since May 2007 until July 2007.
 Mehta served as group managing director of HSBC Holdings PLC of HSBC Finance Corp. since April 30, 2005, and its unit chief executive officer since March 2005.
 He served as the chief executive of HS BC North America Holdings Inc., of HSBC Finance Corp., from March 2005 to February 15, 2007.
 He served as an executive chairman of HSBC Financial Corporation Limited since April 2005 and served as its chief executive officer from April 2005 to February 15, 2007.
 He served as the chief executive officer of HSBC Bank USA, N.A. until February 2007.
 He served as the chief executive officer of HSBC North America Holdings Inc. since March 2005.
 He served as chairman and chief executive officer of HSBC Financial Corp., Ltd.
 He oversaw HSBC's global credit card services, its North American consumer lending and mortgage services businesses and its first mortgage operation.
 He was also responsible for corporate marketing, strategic planning and corporate development for HSBC North America Holdings Inc. and had responsibility for the strategic management of credit cards throughout the HSBC Group.
 Mehta served as group executive of Credit Card Services, Auto Finance and Canada of Household International Inc., since July 2002.
 He worked at MasterCard’s U.S. region board since March 2000.
 Mehta joined Household International Inc., in 1998.
 He served as senior vice president of The Boston Consulting Group in Los Angeles and co-leader of Boston Consulting Group Financial Services Practice in the United States.
 Mehta served as a director of Global Board of MasterCard Incorporated since March 17, 2005.
 He served as unit chairman of HSBC Holdings PLC and served as its board member since March 2005.
 He served as vice chairman and director of HSBC Financial Corporation Limited., (Formerly Household International Inc.).
 He has been a director of Avant Credit Corporation since December 18, 2014.
 He has been an independent director of The Allstate Corporation since February 19, 2014.
 He serves as a member of the advisory board at Core2 Group, Inc.
 He has been non-executive independent director at Piramal Enterprises Ltd since April 1, 2013.
 He serves on the boards of Datacard, Chicago Public Education Fund, University of Chicago Laboratory Schools, The Economic Club of Chicago, The Field Museum and Myelin Repair Foundation.
 He serves as a director of TransUnion Corp. and TransUnion LLC.
 He served as a director of MasterCard International Inc. (also known as MasterCard Worldwide) (formerly, MasterCard Inc.), since March 17, 2005.
 He served as a director of HSBC Financial Corp.
 Ltd.
 He has been a director of TransUnion since April 2012.
 Mehta serves on the board of international advisors for the Monterey, California, Institute of International Studies and is a member of the Financial Services Roundtable.
 He also serves on the board of advisors for the Myelin Repair Foundation.
 Mehta holds a Bachelor of Arts in economics from the London School of Economics and Masters of Business Administration from the University of Chicago.
 He stepped down as head of the North American unit after the lender raised its forecast for bad loans in the U.S.
 He is of Indian descent.
Stephen Martin (born 1966) is a British businessman.
 He served as the chief executive officer of the Clugston Group from 2006 to 2016.
 He is the director general of the Institute of Directors.
The Clugston Group is a privately owned business involved in construction and civil engineering, property development and distribution.
 The group is based in Scunthorpe, North Lincolnshire in England.
Khaled Bichara (Arabic: خالد بشارة‎ ‎ , ] ) (born July, 1971) currently serves as the Chairman of Dada.it, and the Co Chief Executive Officer of Accelero Capital.
 Prior to joining Accelero Capital, Bichara was Chief Executive Officer of Orascom Telecom Media and Technology OTMT, Group President and Chief Operating Officer of VimpelCom Ltd. as well as Group Executive Chairman of Orascom Telecom Holding.
 Bichara played a pivotal role in the 6.6 billion merger of VimpelCom with Wind Telecom S.p.A, to create the worlds sixth telecommunications carrier.
 Before joining VimpelCom, Bichara was the Group Chief Executive Officer of OTH S.A.E.
 He sits on the board of OTH since 2003.
Mike Lunsford is the chief executive officer of SK Planet, Inc., the U.S. arm of SK Planet, Ltd., a Korean-based company.
 He is the former executive vice president and interim chief executive officer of RealNetworks, the former chief executive officer of Rhapsody, a joint venture between RealNetworks and Viacom, and the former president and interim chief executive officer of Earthlink.
 Before joining EarthLink, Lunsford worked as a consultant at Andersen Consulting (now Accenture) in Chicago and Scott, Madden & Associates, a management consulting firm in Raleigh, North Carolina.
 He received an undergraduate degree and a Masters of Business Administration (MBA) from the University of North Carolina.
Bradley Wayne Hughes (born September 28, 1933) is the founder and chairman of Public Storage, the largest self-storage company in America doing business as a REIT or real estate investment trust.
 As of 2014, Hughes is worth $2.2 billion.
 Known all his life by his middle name, B. Wayne Hughes was the company's President and Co-Chief Executive Officer from 1980 until November 1991 when he became Chairman of the Board and sole Chief Executive Officer.
 He retired as Chief Executive Officer in November 2002 and remains Chairman of the Board.
 He was Chairman of the Board and Chief Executive Officer from 1990 until March 1998 of Public Storage Properties XI, Inc., which was renamed PS Business Parks, Inc. ("PSB"), an affiliated REIT.
 From 1989-90 until the respective dates of merger, he was Chairman of the Board and Chief Executive Officer of 18 affiliated REITs that were merged into the Company between September 1994 and May 1998 (collectively, the "Merged Public Storage REITs").
 has been active in the real estate investment field for over 30 years.
Charles E. Bunch (born c. 1950) is an American businessman who served as the chairman and chief executive officer of PPG Industries, Inc., until succeeded by Michael H. McGarry on September 1, 2015.
 Since 2002, he had been a director and prior to becoming president and chief executive officer in March 2005 and chairman and chief executive officer in July 2005, Bunch was president and chief operating officer from July 2002.
 He was the executive vice president from 2000 to 2002 and senior vice president of Strategic Planning and Corporate Services from 1997 to 2000.
 Bunch is also a director of the H. J. Heinz Company and The PNC Financial Services Group, Inc.
 He attended Georgetown University as an undergraduate and received his MBA from Harvard University in 1979.
Glen F. Post III (born October 4, 1952) is the chief executive officer and president of CenturyLink, an S&P 500 integrated communications service provider based out of Monroe, Louisiana.
 He earned a bachelor's degree in accounting in 1974 at Louisiana Tech University and an MBA in 1976 at Louisiana Tech.
 Post joined CenturyTel in 1976.
 He was named vice president in 1982 and was promoted to senior vice president and treasurer in 1984.
 He was appointed to the CenturyTel board of directors in 1985, and the following year he was promoted to senior vice president and chief financial officer.
 In 1988 Post was named executive vice president and chief operating officer.
 He became the president and chief operating officer of CenturyTel in 1990.
 In 1992 Post was named vice chairman of the board, president, and chief executive officer.
 In 2002 he was appointed chairman of the board and chief executive officer.
 Since 2009 Post has served as chief executive officer and president of CenturyLink.
 His honors include: Louisiana Tech College of Administration and Business Distinguished Alumni in 1991, Louisiana Tech University Tower Medallion Award in 1997 and DeGree Enterprises Lifetime Achievement Award in Business 2003.
Stephen M. Wolf (born 1941) assumed his current position as chairman of R. R. Donnelley & Sons Company in March 2004.
 He has been the managing partner of Alpilles, LLC, since April 1, 2003.
 In April 2009 he became chairman of Trilantic Capital Partners, which was previously Lehman Brothers Merchant Banking.
 Before becoming managing partner of Alpilles, Wolf was chairman of US Airways.
 Wolf was chairman and chief executive officer of US Airways from January 16, 1996, until November 18, 1998, when he turned over his chief executive officer title to another executive.
 Wolf was responsible for the company's rebranding to US Airways from its previous identity, USAir.
 During Wolf's tenure, US Airways also placed an order for up to 400 Airbus A320-series narrow-body aircraft, with 120 firm orders at the time of the order signing; at the time, the order was regarded as the largest bulk aircraft request in history.
 Prior to joining US Airways, Wolf had served since 1994 as senior advisor to Lazard Frères.
 From 1987 until it was purchased by its employees in July 1994 he was chairman and chief executive officer of UAL Corporation and United Airlines, Inc.