Amazon.com Inc. (AMZN) is known to enter a market, disrupt it and dominate it. But when it comes to the business of delivering millions of packages to Amazon's customers, United Parcel Service (UPS) and FedEx (FDX) don’t have anything to fear.

That’s according to Wall Street firm Bernstein which thinks that concerns about Amazon Flex are overblown. Amazon Flex is the Seattle, Washington-based e-commerce giant’s crowdsourcing delivery program in which it will pick up third-party merchants packages from warehouses and handle delivery to customers. It's something UPS and FedEx often do for the online retailer. Workers get $18 to $25 hour to deliver packages for Amazon on schedules they set on their own. By launching the service, Amazon not only controls more of the delivery, but it can reduce costs with volume discounts and lower the overcrowding in its warehouses by keeping the products at the merchant’s own locations. (See more: Amazon Tests Delivery Service—Targets FedEx, UPS.)

Crowdsource Delivery Model To Have Little Impact

While news of Amazon Flex has led investors to express concern that business at UPS and FedEx will suffer as result, Bernstein analyst David Vernon argued in a research report that the crowdsourced delivery model will have little impact on the overall market. “We see limited risk of full-scale diversion of volume from traditional carriers to crowdsourced models due to the constraints required to build efficient flex blocks and limitations on supply of ‘right-timed’ labor,” the analyst wrote in a research report covered by the media. “It will remain a marginal source of capacity for the e-retail industry.”  The analyst has an outperform rating on UPS and FedEx and price targets of $137 and $296 respectively. At $137 Vernon thinks shares of UPS can climb 19%. He’s forecasting an 18% upside for FedEx. (See more: Would 'Shipping with Amazon' Kill UPS and FedEx?)

Amazon Flex Can’t Compete With Full-Time Workers

Take the labor aspect of it. According to Vernon, the pay rates for Amazon Flex workers and other crowdsourced delivery platforms can’t compare with full-time jobs offered by UPS and FedEx. There’s also a risk that if the model grows retailers will have to  "reach further down the couch for drivers, the quality and cost of this option can change for the worse (particularly for gigs that don't tip)." The analyst noted crowdsourcing delivery models are best suited for peak season, which he said wasn’t a negative for delivery companies either. Take the holiday selling season for one example. FedEx and UPS are forced to hire more drivers to meet the heightened demand during that period. A crowdsourcing delivery model could give them a bit of a break during those peak times.

The analyst acknowledged that this new model of getting packages to consumers’ homes is here to stay but said it won’t be as disruptive as some investors fear.  “We do not see the growth of crowdsourced delivery models as destabilizing to the capacity and pricing picture for residential small package delivery,” wrote Vernon.