Alliance Data Systems ( ADS) is all about customers - their customers' customers, that is. The firm provides marketing and loyalty services for other companies, handling more than 120 million customer relationships with a specific focus on Canada, where its Air Miles subsidiary operates. From gas stations to airlines to banks, Alliance Data is all about outsourced customer relationships. That's proven to be a lucrative business for ADS. The firm earns double-digit net margins for its trouble, while at the same time building itself an attractive moat. With clients' customer lists and very long-term contracts as standard, revenues are stickier than they would be if ADS didn't own many of the networks that it administers for firms. ADS has also established itself as a major player in the private-label credit card business, processing transactions on behalf of retailers who don't want the hassle or balance sheet risks of issuing cards themselves (for its part, ADS securitizes its receivables, so little credit risk remains on its balance sheet). ADS currently sports a short interest ratio of 13.7, which means that it would take short sellers close to three weeks to cover their positions. That puts this $6.7 billion firm directly in line with our market-beating strategy this summer. To see this week's short squeezes in action, check out the of Large-Cap Short Squeezes portfolio on Stockpickr. -- Written by Jonas Elmerraji in Baltimore.