Eleventh-Hour Bulls Rush to Ambarella, Inc. (AMBA)

Ambarella Inc (NASDAQ:AMBA) has been nothing short of phenomenal from a technical perspective, with the shares more than doubling in value during the past 52 weeks and outperforming the S&P 500 Index (SPX) by over 41 percentage points in the last three months. Earlier today, the security touched an all-time high of $73.00, and was last seen 5.2% higher at $72.82, leading speculators to place bullish bets at a rapid-fire rate. In fact, calls are crossing at twice the expected intraday pace.

Receiving notable attention today is the March 72 call, which expires at 4 p.m. ET today. There's possible buy-to-open activity here, meaning traders are betting on AMBA to extend its lead further north of $72 through today's close.

Call buying has been a popular strategy in the security's options pits of late, as more than three calls have been bought to open for ever put during the past two weeks at the International Securities Exchange (ISE), Chicago Board Options Exchange (CBOE), and NASDAQ OMX PHLX (PHLX). The resultant call/put volume ratio of 3.06 lands in the 87th percentile of its annual range.

However, over 32% of Ambarella Inc's (NASDAQ:AMBA) float is sold short. At the stock's normal daily trading pace, it would take nearly six sessions to repurchase those bearish bets. It's possible that some of the recent call buying is the result of bears hedging their bets.