Bears have been circling the wagons around Atheros Communications (ATHR). During the month of June, open interest in ATHR puts has increased from less than 11,000 to almost 58,000. A week ago, open interest in ATHR puts was about 20,000 (Click chart.) Trades this week include a buyer of 4,000 Sept 15 – 17.5 puts Tuesday–a bearish bet that yields its best profits if ATHR falls to $15 or less.

The action continues today, with another 12,000 puts traded, or 9X the typical levels. Some of the activity might be closing trades, after Amtech and Roth Capital both upgraded ATHR to Buy this morning. Nevertheless, the surge in open interest in ATHR puts is certainly noteworthy, as it seems to reflect some anxiety about the near-term outlook for the Santa Clara, CA integrated circuit maker.