Warehouse club Costco Wholesale (COST -0.24%) once again impressed investors last week, reporting another quarter of robust same-store sales growth, strong e-commerce momentum, and impressive membership renewal rates. Indeed, the company's renewal rates -- both globally and in its core U.S. and Canada markets -- hit record highs during the period.

For investors looking for more information about the company's solid operating results, consider some of the following key quotes from Costco's fiscal fourth-quarter earnings call. During the call, management provided some insight into its record membership renewal rates, e-commerce, and more.

A grocery cart in a shopping aisle at at wholesale store.

Image source: Getty Images.

Record membership renewal rates

"In terms of renewal rates, at Q4 end, our U.S. and Canada membership renewal rate came in at 90.9%, up 0.2% from 90.7% as of the end of the last quarter," said Costco CFO Richard Galanti during the company's fiscal fourth-quarter earnings call (via a Thomson Reuters transcript). "And worldwide, the renewal rate was 88.4%, up from 88.3% a quarter ago, both of these figures all-time highs."

This uptick is particularly impressive since renewal rates were at a record high in the company's previous quarter as well. So the previous quarter wasn't an easy comparison.

Not only were renewals impressive, but the company ended the fourth quarter with 20.8 million executive memberships -- up 362,000 sequentially. This means the company added 23,000 new executive members per week during the period.

Strength in e-commerce

The company's e-commerce sales continue to grow much faster than its total business. Same-store e-commerce sales rose 19.8% year over year during the period, or 21.9% when adjusted to exclude fuel sales. This compares to 5.1% total company same-store sales growth.

Galanti credited this strength in digital sales to "particularly strong growth during the quarter in what we call majors, electronics and appliances and the like." Further, the CEO also noted that its online grocery sales grew "at a very healthy clip" but emphasized that this growth is on a small base.

A surprisingly robust jewelry business

While most people likely associate Costco with wholesale groceries and value-priced household goods, the company is also thriving in the luxury jewelry segment.

A few quarters ago, Costco received a lot of attention in the press because it sold a $400,000 diamond. But this only represents a small fraction of sales in its jewelry business.

"We're selling close to 200,000 carats of diamonds a year. That's a lot of carats," said Galanti. Explaining what's behind this success, Galanti said, "it's all about value and trust."

The company is clearly prioritizing jewelry sales, as it has positioned its jewelry near electronics, toward the entrances of its stores.

Overall, the quarter was solid -- and it continued to highlight a company that is rewarded with strong sales growth for its efforts to deliver value to its members.