Option players have been accumulating puts on Zillow Inc (NASDAQ:Z - 45.63), per data at the International Securities Exchange (ISE), Chicago Board Options Exchange (CBOE), and NASDAQ OMX PHLX (PHLX). Over the course of the past 20 sessions, traders on these major exchanges have bought to open 581 puts for every 100 calls.

This trend has translated into a put-skewed Schaeffer's put/call open interest ratio (SOIR) for the stock. Specifically, Z's SOIR of 1.82 ranks in the 94th percentile of its annual range, meaning short-term speculators have been more put-heavy just 6% of the time during the past year.

Puts emerged as the options of choice throughout Thursday's session. More than 5,300 contracts traded, representing nearly three times the average daily pace for put options. By contrast, fewer than 3,000 call contracts crossed the tape. Near-term traders placed their bets on the September 45-strike put, which saw roughly 1,700 contracts cross the tape. However, with the majority of the contracts trading at the bid price, and open interest rising overnight, it seems some of these speculators bucked the recent bearish bias, and opened new neutral-to-bullish short put positions on Z.

By selling these short-term puts to open, traders are expecting Z to maintain its perch above the $45 mark through the end of today's session, allowing them to pocket the initial premium collected, or $0.62 (the volume-weighted average price). With implied volatility at the strike currently inflated in relation to its 20-day historical (realized) volatility (66% v. 48%), now appears to be an opportune time to sell premium on the September 45 put, as opposed to buy it.

On a technical basis, Z's time on the charts in 2012 has been nothing short of impressive, with the shares more than doubling in value on a year-to-date basis. Highlighting this upward momentum has been the stock's 20-week moving average, which has pushed Z steadily higher since mid-January. What's more, the equity touched a new 52-week peak of $46.86 on Thursday.

While Z has pulled back from this technical milestone in today's session, the stock was last seen sitting solidly north of the $45 level.

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