Costco is still cheaper than Whole Foods

A customer browses goods at a Costco Wholesale store in New York.
Victor J. Blue | Bloomberg | Getty Images

Competition is heating up in the grocery industry.

Amazon's recent acquisition of Whole Foods and the subsequent price reductions have led customers to question if the chain — which had earned the moniker "Whole Paycheck" — truly provides significant savings or if it's just as expensive as ever.

For members of Costco, which has long been a secret weapon for customers aiming to cut down their grocery bills, the wholesale club still seems to be the better bargain. Recent data from JPMorgan found that Costco remains a "whopping" 58 percent cheaper than Whole Foods on a per-unit basis for groceries.

"[Costco] offers an unquestioned value prop with the best pricing, curated assortment, strong private label offering, and treasure hunt atmosphere," JPMorgan analyst Christopher Horvers wrote in a note to clients, as reported by CNBC.

The 'new' Whole Foods vs. Trader Joe's: Which is cheaper?

Costco also proved the least expensive option for perishable groceries, dry goods and household items when compared to Whole Foods, Wal-Mart, Target and Aldi, JPMorgan found.

But as competition among supermarkets intensifies, winning loyalty from young, millennial customers will prove increasingly valuable.

Costco has already made some moves to keep up with recent trends by launching two new delivery options, CNBC reports. The first, Costco Grocery, offers shoppers about 500 nonperishable goods for two-day delivery, with orders over $75 dropped off at no charge.

A second service, offered in metropolitan markets and powered by Instacart, lets shoppers choose from 1,700 items, including fresh groceries, for same-day delivery.

Correction: A previous version of this story inaccurately stated that Costco does not sell the beverage brand LaCroix.

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