GrubHub Inc (NYSE:GRUB) stock is trading up 3.3% at $65.22, on reports investment research firm Hedgeye thinks the food delivery name could be bought out by Amazon (AMZN). In addition, the analyst allegedly sees 60% to 100% upside for GrubHub shares. GRUB options traders are getting in on the action, too, placing bullish bets at an aggressive pace.

Most recently, 12,500 GrubHub call options were on the tape, nine times what's typically seen at this point in the day, and seven times the number of puts. Day traders appear to be buying to open the weekly 6/7 64- and 65-strike calls, which expire at tonight's close, while longer-term speculators look to be purchasing new positions at the September 90 call. The volume-weighted average price on this deep out-of-the-money call is $1.34, which makes breakeven at September expiration $91.34 (strike plus premium paid).

Widening the scope reveals put buyers have been targeting GRUB at a quick clip in recent weeks. At the International Securities Exchange (ISE), Chicago Board Options Exchange (CBOE), and NASDAQ OMX PHLX (PHLX), the equity's 10-day put/call volume ratio of 0.76 ranks in the 71st annual percentile. So, while calls have outnumbered puts on an absolute basis, the rate of put buying relative to call buying has been faster than usual.

This skepticism has been seen outside of the options pits, too. Short interest on GRUB jumped 10% in the most recent reporting period, to 17.39 million shares. This accounts for almost one-fifth of the stock's available float, or 5.5 times the average daily pace of trading.

Looking at the charts, GrubHub shares had a rough start to 2019, but recently found a familiar floor near $60 -- a round-number level that served as support in November 2017 ahead of the equity's rally to a record high of $149.34 that following September. Since a successful test of this region earlier this week, GRUB stock has added almost 8%.