GrubHub Inc (NYSE:GRUB) reported third-quarter adjusted earnings of 27 cents per share -- in line with the consensus estimate -- on $322 million in revenue, well below the $330.5 million analysts were expecting. The company also gave lower-than-anticipated current-quarter guidance amid rising competition in the food delivery space.

In a letter to shareholders, GRUB CEO Matt Maloney said the firm will be "spending more and trying many different strategies over the next 12-18 months," including "investing aggressively in our independent restaurant sales organization." This plan has drawn a quick reaction from analysts, with Guggenheim downgrading GrubHub stock to "neutral" from "buy," saying the strategy is "unproven," and creates "greater uncertainty."

Craig-Hallum also lowered its rating on GRUB shares, to "hold" from "buy," and slashed its price target by $60 to $40. Prior to today, most analysts were bullish on the equity, with 13 maintaining a "strong buy" rating, compared to eight "holds," and one "strong sell." Meanwhile, the average 12-month price target of $81.42 is still a 56.7% premium to current levels.

Against this backdrop, GRUB stock hit a two-year low of $35.15 out of the gate, and was last seen down 39.6% to trade at $35.26. This puts the equity on the short-sale restricted list, and has options activity running hot in early trading. Already today, roughly 21,000 contracts have crossed -- a near-even split between calls and puts -- surpassing the average daily volume of 9,045 options. The November 35 put is most active, and new positions are being initiated here.