Costco Wholesale (COST 1.68%) has been on a tear since early 2020, gaining market share and capitalizing on a recent surge in consumer spending. The only month for which it reported weak results last year was April, which arguably represented the peak of the COVID-19 pandemic (and related lockdowns) in the U.S.

This set Costco up to post its biggest sales gains yet last month. Sure enough, the warehouse club titan delivered in spectacular fashion.

Sales growth accelerates in April

In March, Costco's adjusted comparable sales (excluding the impacts of gasoline price changes and currency fluctuations) rose 11.1% year over year. This result was especially remarkable because the retailer faced a tough comparison after posting a 12.3% adjusted comp sales gain a year earlier. Additionally, the timing of Easter reduced Costco's March comp sales growth by as much as 2 percentage points.

The entrance to a Costco warehouse

Image source: Costco Wholesale.

By contrast, Costco's adjusted comp sales ticked down 0.5% in April 2020, as stay-at-home orders limited retail traffic and consumers reduced spending after stocking up on essentials during late February and March. This meant that Costco faced an extremely easy year-over-year comparison last month.

On Wednesday, the retail giant announced that adjusted comparable sales jumped 24.2% in April. The timing of Easter lifted monthly sales by about 2.5 percentage points. Including the tailwinds from a weaker dollar and higher gas prices, comp sales skyrocketed 32.5% and total sales rose 33.5% to $15.21 billion.

These sales results topped analysts' expectations. That helped Costco stock gain ground on Thursday, edging closer to the all-time high it reached late last year following a dip a few months ago.

COST Chart

Costco stock performance, data by YCharts.

Another good sign for the future

The pandemic seemed to help Costco's sales for most of last year. For example, consumers bought more food (while eating at restaurants less frequently), purchased new home furnishings, and invested in big-ticket items like appliances and electronics.

Naturally, many investors feared that as pandemic restrictions eased, these tailwinds would reverse, leading to weak sales results for much of 2021. It's becoming increasingly clear that those fears were unwarranted. For the past two months, adjusted comp sales have increased by 23% to 24% relative to 2019. This suggests that even when Costco starts to lap tougher comparisons in the months ahead, it should be able to continue recording solid comp sales gains.

Indeed, while comp sales growth for food-related items moderated to less than 10% in April, comp sales surged more than 40% for non-food items and more than doubled in Costco's ancillary businesses. Demand for home furnishings remains extremely high. Meanwhile, the ongoing reopening of the U.S. economy is unleashing demand for apparel, jewelry, and gasoline. Customers are returning to Costco's optical and hearing aid departments, too.

Globally, consumers have an estimated $5.4 trillion of excess savings -- nearly half of that in the U.S. -- due to reduced spending on travel, restaurants, and entertainment during the pandemic. That should keep demand humming in 2021 and beyond across a wide range of discretionary categories. Costco is poised to continue capitalizing on this wave of consumer spending for the foreseeable future.