Investors in Costco Wholesale (NASDAQ:COST) have gotten good long-term performance from their holdings, as the warehouse retailer has done a good job of navigating changing trends in retail while still remaining true to its product-hungry core shoppers. Yet even as the stock trades near all-time highs, some Costco investors worry that they could be vulnerable to growth in e-commerce that might lure some shoppers away -- especially as the warehouse giant implements a membership price increase.

Costco is slated to release its fiscal third-quarter financial report on Thursday, May 25. To satisfy those following the stock, the company will have to demonstrate its ability to keep growing even under growing competition from online retail. Let's take an early look at Costco and what we're likely to see when it reports its quarterly numbers.

Key stats on Costco

Expected EPS Growth

5.6%

Expected Revenue Growth

6.5%

Forward Earnings Multiple

26.9

Expected 5-Year Annualized Growth Rate

10%

Data source: Yahoo! Finance.

Can Costco earnings keep climbing?

In recent months, investors have grown concerned about Costco's earnings growth. They've reduced their fiscal third-quarter numbers by $0.05 per share, and they've made more extensive cuts to their views on the full 2017 and 2018 fiscal years. The stock has nevertheless held its own despite those earnings concerns, with flat returns since mid-February.

Costco's fiscal second-quarter results showed some of the pressures that the company has had to deal with recently. Sales were strong, resulting in a 6% rise in total revenue for the retail giant. But profitability went in the wrong direction, with a 6% drop in earnings that disappointed investors, most of whom were looking to see earnings growth compared to the year-ago quarter. Comparable-store sales growth of 3% systemwide reflected the rebound in gasoline prices, but sluggish growth figures in membership revenue and a slowdown in the pace of expansion of new stores weren't what most of those following the stock had wanted to see.

In response, Costco said it would finally implement a long-awaited membership-fee increase. Effective June 1, the cost of a standard annual membership will rise $5 to $60 per year, while the price of executive memberships will climb by $10 to $120 per year. The move will affect about 35 million members, and Costco hopes to reap roughly $260 million to $265 million if all of its members hang onto their memberships after the price increase. To help give an incentive for high-value executive members to stay, Costco also increased the maximum cash-back reward that they're entitled to receive from $750 to $1,000. That way, the retailer hopes to keep its best customers happy while still bringing in new membership revenue.

The Costco logo.

Image source: Costco.

Still, competitive threats abound. A recent report suggested that online retail giant Amazon.com (NASDAQ:AMZN) might seek to enter the brick-and-mortar warehouse retail market aggressively by buying privately held BJ's Wholesale Club. BJ's has a mostly regional presence, with its locations concentrated along the Eastern Seaboard, especially the Northeast. Yet Amazon is big enough and has enough financial resources that if the experiment went well, it could quickly seek to expand nationwide, either by using the BJ's brand or by building up its own set of competing locations. Either one of those scenarios would present a crisis situation for Costco, forcing it to handle a direct assault on its business model even as it has traditionally argued that it could fend off Amazon because of customer preferences toward shopping in physical locations rather than solely online.

When Costco releases its earnings report, it'll be important to see both sales growth and better profits. Without both components of financial strength, Costco will face ongoing questions about whether its membership-fee increase and other strategic moves will be enough to hold off adverse retail trends for the big-box giant.

Dan Caplinger has no position in any stocks mentioned. The Motley Fool owns shares of and recommends Amazon and Costco Wholesale. The Motley Fool has a disclosure policy.