Intel already has web hosting contracts with the BBC and Indian stock exchange and the move underlines the drive of giant hardware companies into the e-business services market.
Intel will take responsibility for managing the Amex network infrastructure, including data back-up, Web site servers and operating system software for Amex Web sites.
It has developed customised monitoring capabilities to manage the network that connects the Amex to third-party data providers who deliver real-time financial information.
Joanne Watson, business development manager at Intel Online Services, said: "Intel Online Services has been going for two and a half years. It complements our core business and is the biggest services division we have. It is absolutely strategic for us to become an e-business supplier."
Intel would not give details to the size of the Amex deal apart from saying: "It is not our biggest," and claimed to have a number of similar sized contracts.
"Intel are branching out," said Andy Brown, analyst at research group IDC. "They are well known for chips but they are looking to generate revenue from other areas. Basic processor sales are no longer a cash cow as PC sales have plummeted. They are becoming a more flexible organisation and looking at areas like mobile wireless."
Fellow IDC analyst Euan Davis added: "Intel is moving hard into the area of web hosting. They have the biggest state-of-the-art data centre in the UK and have a tremendous brand which they are using to make headway."
Intel's Watson said that despite the dotcom gloom, Intel Online Services has had "a significant increase in deals in the last few months. Flakey dotcoms may have crashed, but more bricks and mortar companies are coming to us for their internet applications. The quality and the quantity are improving."