Maplebear Inc. (CART) shares took a hit in Monday's after-hours session as investors digested news that Amazon.com Inc. (AMZN) is gearing up to launch an ultrafast delivery option that could deliver groceries and household staples in under 30 minutes.

What's Happening: According to a recent report from The Information, Amazon is preparing to roll out this speedier delivery service in select major cities first. Think Seattle, Philadelphia and Fort Worth as the initial testing grounds.

For Maplebear—the parent company behind Instacart—this is unwelcome news. Speed and convenience have been Instacart's bread and butter, the main reasons customers choose the platform over trudging to the grocery store themselves. Now Amazon is coming for that exact advantage.

The timing stings a bit more because Maplebear had been riding high lately. Shares climbed about 15% over the past month after the company posted solid third-quarter earnings in November, showing orders jumped 14% year-over-year. Momentum was building.

But competitive threats have a way of changing sentiment quickly. Maplebear shares dropped roughly 3.95% in extended trading, hovering around $41.10 at publication time. Meanwhile, Amazon shares ticked up 0.31% to $234.60 in after-hours trading, adding to a 0.28% gain during the regular session.

What Analysts Think

Wall Street's overall take on Maplebear remains a Buy based on coverage from the past three months. Bernie McTernan from Needham stands out as the most cautious voice, projecting a potential 24.24% decline over the next year.

Recent price action tells a somewhat different story. Over the past three months, Maplebear climbed 13.1%, suggesting investors had grown more optimistic about the business fundamentals. Revenue backed up that confidence, rising 10.21% year-over-year.

The question now is whether Amazon's ultrafast delivery plans will chip away at that momentum or if Instacart's established presence and partnerships can hold the line against the e-commerce giant's latest move.