The business value of airline firm investments in computerized reservation systems (CRSs) has been documented in the businesspress,governmentlitigationandincasestudies,butjustacouplestudiesofferempiricalresults. Thisresearchextends what we know about the dynamics of airline market share creation as a result of travel agency automation. (“Market share” is commonly understood to mean the portion of total revenue passenger miles captured by an individual carrier from an origin to a destination city-pair.) At another more general level, it aims to deliver modeling and methodological insights that bear on contemporary settings in which information technology (IT) is employed in the marketing mix. In electronic commerce, for example, these include the use of point-of-sale debit systems or electronic money as ways-to-pay, web-based versus traditional corporate advertising, and participation in electronic markets for the sale of physical goods.