Grocery retailers could see price wars intensify as Amazon.com Inc. (AMZN) may be gearing up to offer its Prime subscribers more perks. Amazon's efforts could ramp up sales at its hundreds of its new brick-and-mortar locations and steal market share away from traditional industry leaders such as Kroger Co. (KR), Walmart Inc. (WMT) and Costco Wholesale Corp. (COST). 

The Seattle-based e-commerce and cloud computing giant celebrated the close of its $13.7 billion buyout of the natural foods grocer in August. Shares of rivals tanked as Amazon slashed prices on many products at the retailer, nicknamed by cost-conscious consumers as "Whole Paycheck." The Street has applauded Amazon's ability to drive market share gains at Whole Foods and boost its monthly Prime subscriber base after the buyout. (See also: Amazon: Whole Foods Price Cuts to Boost Prime Subs.)

Prime Perks Ignite Competition 

This week, news broke that a Whole Foods in Austin, Texas, tested banners proclaiming 10% discounts at the grocer for members of its growing Prime program. The discounts are not official and the marketing materials are still in their trial stages, according to CNBC. The banners were hung late on Wednesday and were removed by Thursday morning. One banner targeted Amazon Prime members, reading "Blue signs mean special deals just for you, yes you." Another sign indicated that Prime members save an extra 10% off "hundreds of sale prices."

Earlier this year, Amazon announced that its Prime members who use its Visa rewards card will receive 5% cash back when they shop at Whole Foods. Its monthly subscribers have been offered various perks, such as an exclusive discount when purchasing roses at Whole Foods during Valentine's Day. Jeff Bezos' retail behemoth has been rolling out a free delivery service for Whole Foods products for its Prime members, aiming to expand its online grocery delivery to about 800 stores by year end.

While Amazon has been quiet on the number of customers who use its Prime membership, which ranges from $10.99 to $12.99 per month, many on the Street say that more than 50% of U.S. households are part of the group. One of the most ambitious figures came from keynote speakers at the Internet Retailers Conference and Exhibition (IRC) in June, who estimate that 64% of households have a Prime membership, as cited by Forbes. 

Kroger, Target Join Forces

In a hedge against Amazon's rising dominance in both the online and offline retail spheres, Kroger has announced a deal with Target Corp. (TGT). The move would provide Kroger with infrastructure for a competitive online retail and merchandise business and enhance Target's grocery stores. 

Closing up 1.1% on Thursday at $1,447.34, AMZN extended this year's 23.8% gain versus the S&P 500 index's 1.2% loss in the period. Earlier this week, news broke citing a White House insider who indicated that President Donald Trump is "obsessed" with taking down Jeff Bezos and his "everything store," sending shares down 6.3% in the most recent five-day-period. While Facebook Inc. (FB) has been the hardest hit amid the recent tech sell-off, due to its involvement in a massive data scandal surrounding Trump campaign-affiliated Cambridge Analytica, sources indicated that the president is not very interested in Facebook but rather has his mind set on punishing Amazon. (See also: Amazon at $1,900 Possible This Year: Goldman.)