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September started off with back-to-back major hurricanes slamming into the United States, but the markets continued to trade at all-time highs throughout the month. Judging by most shorted stocks traded on the Nasdaq between the September 15 and September 29 settlement dates, short sellers overall were cautious. That is, the short interest moves among these stocks were mixed and mostly modest.

The stand out was toy and game maker Mattel, which rose into the top six on a wave of rising short interest going back to the summer, well before the announced bankruptcy of  Toys “R” Us. Also, short sellers shied away from a couple of biotech stocks, but not enough for them to slip out of the top 10.

Note that still just three Nasdaq stocks had more than 100 million shares short as of the end of last month.

Sirius XM

The more than 232.83 million Sirius XM Holdings Inc. (NASDAQ: SIRI) shares short after the latter two weeks of last month was more than 9 million less than on the previous settlement date, and it was the smallest number of shares short so far this year. The latest reading represented 16.2% of the total float. The average daily volume shrank to a year-to-date low as well, so the days to cover increased from near 12 to more than 17.

During the period, at least one analyst saw upside potential in Sirius. The stock ended the short interest period barely higher than where it began it, though they gained more than 3% afterward. The Nasdaq rose fractionally between the settlement dates. Sirius shares closed most recently at $5.65 apiece. That is still down from the 52-week high of $5.89 seen near the end of July. The 52-week low of $4.05 was reached last fall.

AMD

At the end of September, Advanced Micro Devices Inc. (NASDAQ: AMD) had more than 160.53 million shares short. That was a rise of less than 2% from the total on the previous settlement date, but it was the highest level of short interest in at least a year. The most recent reading represented 18.2% of the company’s float. It still would take a little more than two days to cover all short positions.

During the period, one analyst saw big upside potential in AMD. The September 29 share price was less than 2% higher than on the previous settlement date, though the shares were up more than 9% at one point in the interval. The stock closed on Tuesday at $13.70, which is more than 4% higher than six months ago. Shares have changed hands between $6.22 and $15.65 apiece in the past year.

Intel

More than 116.01 million Intel Corp. (NASDAQ: INTC) shares were sold short as of the latest settlement date. Short interest decreased nearly 2% during the period, ending three consecutive periods of rising numbers of shares short. But it was still the second highest level of short interest in the past year, and it represented 1.9% of the company’s float. As of the latest settlement date, it would take about five days to cover all short positions.

This semiconductor giant remains an old-school tech favorite on Wall Street. Though its shares ended the short interest period with nearly a 3% gain, they have added that much and more again since then. The most recent close at $39.65 a share compares to a 52-week trading range of $33.23 and $39.95. Furthermore, the share price is more than 9% higher than at the beginning of the year.

Opko Health

Opko Health Inc.’s (NASDAQ: OPK) short interest decreased almost 5% from in the previous period to more than 72.69 million shares on the most recent settlement date. That was the fewest shares short since back in January, and it was 22.0% of the total float. The daily average volume reached a multi-month high during the two weeks, and the days to cover number dropped from more than 13 to around 11.

For well more than a year, the CEO frequently has bought batches of Opko shares. The stock closed most recently at $6.88 a share, in a 52-week trading range of $5.85 to $12.15. During the two-week short-interest period, the share price increased around 15%. However, it has been relatively flat in the past week and is still more than 9% lower than it was six months ago.

Mattel

Mattel Inc. (NASDAQ: MAT) saw the number of its shares short grow by more than 15 million by the end of the month. The more than 63.07 million shares reported represented 18.5% of the toymaker’s total float. Note that short interest has been on the rise since June and as of the latest settlement date is the highest it has been in the past year. At the posted average daily trading volume, it would take about six days to cover all short positions.

Toy and game retailer Toys “R” Us declared bankruptcy during the settlement period. In the final two weeks of the month, Mattel stock tumbled more than 8% but recovered to end down less than 3%. Shares rose a little more afterward. Tuesday’s closing share price was $15.51, which is still down about 39% in the past six months. In the past year, the shares have traded between $14.35 and $33.23 apiece.

Synergy Pharmaceuticals

Short interest at Synergy Pharmaceuticals Inc. (NASDAQ: SGYP) totaled almost 62.73 million shares on September 29, which was around 6% lower than on the prior settlement date. That represented a whopping 28.0% of the total float and was the smallest number of shares short seen since July. The days to cover rose from near nine to more than 14 during the latest period as the average daily volume dwindled.

This biopharmaceutical company is focused on treatments for constipation and irritable bowel syndrome. Short sellers watched the stock sink almost 5% but then jump back into the black at the end of those two weeks. The most recent closing share price was $3.35, which is about 23% lower than six months ago. The shares have traded hands between $2.56 and $7.15 apiece in the past year.

And Others

Rounding out the top 10 were Comcast Corp. (NASDAQ: CMCSA), Cisco Systems Inc. (NASDAQ: CSCO), Micron Technology Inc. (NASDAQ: MU) and Novavax Inc. (NASDAQ: NVAX). Among these, Novavax saw a double-digit percentage decline in its short interest, while the others had the number of their shares short rise, led by Micron.

Lingering just outside the spotlight of the top 10 most shorted Nasdaq stocks were Ascena Retail Group Inc. (NASDAQ: ASNA), BlackBerry Ltd. (NASDAQ: BBRY), Microsoft Corp. (NASDAQ: MSFT) and Oclaro Inc. (NASDAQ: OCLR).

Note that Apple Inc. (NASDAQ: AAPL) continued to slip well out of the top 10 during the period, as it has since the new iPhones and Apple Watch were introduced.