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GrubHub Inc (NYSE:GRUB) shares dropped on Tuesday in the wake of a disappointing earnings release Monday with US broker Oppenheimer moving to downgrade its rating for the online food delivery group to ‘Underperform’ from ‘Outperform’.

Oppenheimer slashed its price target for GrubHub to $34 from $91, with the stock plunging by 41% to $34.76 in morning trade.

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A day ago, GrubHub posted third-quarter sales of $322 million, falling short of Wall Street’s prediction of $330.5 million.  It also disappointed investors by projecting that its fourth-quarter revenue would fall between $315 million and $335 million, missing the target of $387 million set by analysts.

Competition from rivals like Uber and Doordash are threatening GrubHub’s foothold in the food delivery market and this trend looks set to worsen in the fourth quarter, according to Oppenheimer’s analysts.

In a note to clients, the analysts said: “Competitive food delivery offerings are eroding the company’s usage, suggesting historical LTV (long-term value) is no longer reliable. This is driven by better restaurant selection, subscription, loyalty plans and end-to-end experience.”

In a bid to distinguish itself from the pack, GrubHub is refocusing on forays into lower-margin areas, such as adding non-partner restaurants and devising new diner promotions.

“We think this will accelerate industry consolidation, but GRUB has a weaker currency than the two largest players and we see investor demand with slowing growth and declining EBITDA,” the analysts added.

On the upside, GrubHub is seeing a “higher-than-anticipated” surge in new diners thanks partly to a marketing push and the striking of new partnerships with chain restaurants could draw even more eaters.

Oppenheimer’s analysts also said other risks to its bearish price target include possible industry consolidation and new subscription offerings that ratchet up dinner orders.

But overall they argued that the picture isn’t particularly rosy for GrubHub as more diners defect to competitors, and forecasts of a warm winter could also hit online food sales.