It's no secret that Costco (NASDAQ:COST) is a fantastically successful business. The warehouse giant built the world's second-largest retailing platform using a few key competitive advantages, which are reflected in its steady market share gains and elevated customer loyalty.

Many of the chain's real strengths aren't obvious from just following the headline results that Costco reports each quarter. This isn't your normal retailing business, after all, considering that most of its earnings are generated from membership fees rather than product markups.

So with that in mind, let's look at a few key highlights from Costco's recent quarterly report that you might have missed at first glance.

A woman shops in the meat section of a market.

Image source: Getty Images.

1. Growth is being held back by gas demand

Costco is enjoying elevated demand, like most of its peers in the consumer staples niche. That spike extends beyond essentials like groceries and into discretionary items such as consumer electronics and home furnishings. It reported a 17% boost in comparable-store sales for the fiscal first quarter through Nov. 22.

That figure adjusts for exchange rate shifts and changing gas prices. But it doesn't account for the temporary decline in gas demand due to COVID-19 travel pressures. Factor that shift in, management explained in Costco's 10-K report back in October, and Costco's comps figure would have been higher by 0.5% in the fiscal year that ended in August. The temporary gas pressure extends to other areas of the business, too, which often benefit from extra traffic after members fill up their tanks.

2. Almost everyone renews their membership

Costco's membership renewal rate, arguably the most important single metric for investors to follow, isn't revealed in its quarterly reports but instead is posted in annual filings and described in the chain's regular conference call updates with Wall Street analysts.

Management said this week that the rate held steady at 91% in the core U.S. market. That's near the company's all-time record and compares well with rivals like BJ's Wholesale (NYSE: BJ), which tracks renewals at 87%.

Costco's renewal rate is even more impressive when you consider how easy it is to cancel a subscription. Simply tell the company you aren't satisfied, and you'll get a full refund -- not just a prorated one -- immediately. It's a testament to the value it offers that the chain can still convince almost all of its shoppers to renew each year.

3. Still a cash-rich business

Costco promises a steady, modest quarterly dividend just like retailing peers Walmart and Kroger. But in practice, that payout is both higher and much more volatile, often rising to well over 100% of earnings in a given year.

COST Payout Ratio Chart

COST Payout Ratio data by YCharts.

That's due to management's preference for occasional special dividends that have happened every few years. Executives like the flexibility they get from not being committed to a large quarterly payout but can still make moves like the recent $10-per-share outlay.

That flexibility is an even bigger asset right now given that economic growth is so volatile. "We could have [paid more]," CFO Richard Galanti said in this week's conference call. "[But] we still don't know what's going to happen with COVID and what may happen next year in the economy." That's why Costco is choosing to enter 2021 with a bit more cash at its disposal than it usually would following a huge year for sales growth.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.