The beginning of October not only ushered in the fourth quarter, but a time of the year when the markets can be volatile. The bull run approached nine years long, and yet the markets continued to reach new highs. Judging by the most shorted stocks traded on the Nasdaq between the September 29 and October 13 settlement dates, short sellers were growing selective. While the short interest moves among these stocks were mixed, the upswings tended to be more robust than the downswings.

Comcast, Intel and Mattel led this trend, each with double-digit percentage growth in the numbers of its shares sold short earlier this month. On the other hand, short sellers shied away somewhat from those stocks that top this list yet again: Sirius XM and AMD.

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

Sirius XM

The more than 227.00 million Sirius XM Holdings Inc. (NASDAQ: SIRI) shares short after the first two weeks of this month were almost 6 million less than on the previous settlement date, and that  was the lowest level of short interest so far this year. The latest reading represented 15.8% of the total float. The average daily volume rose from a year-to-date low, so the days to cover slipped from more than 17 to less than 16.

During the period, Sirius hiked its dividend by 10%. The stock ended the short interest period more than 3% higher than where it began it, though most of that gain came in the first couple of days of the month. The Nasdaq rose less than 2% between the settlement dates. Sirius shares closed most recently at $5.72 apiece. That is less than the 52-week high of $5.89 seen near the end of July. The 52-week low of $4.05 was reached almost a year ago.

AMD

By the middle of October, Advanced Micro Devices Inc. (NASDAQ: AMD) had more than 148.60 million shares short. That was a decline of more than 7% from the total on the previous settlement date, which was the highest level of short interest in at least a year. The most recent reading represented 16.8% of the company’s float. It would take a little more than three days to cover all short positions.

Despite the run up in the industry, AMD appeared during the period to still have upside potential. The October 13 share price was more than 11% higher than on the previous settlement date, though the shares have retreated a bit since then. The stock closed on Tuesday at $14.25, which is more than 8% higher than six months ago. Shares have changed hands between $6.22 and $15.65 apiece in the past year.

Intel

Approximately 131.85 million Intel Corp. (NASDAQ: INTC) shares were sold short as of the latest settlement date. That was the greatest level of short interest in at least the past year, as the figure grew by almost 16 million shares, or more than 13%. And it represented 2.8% of the company’s float. As of the latest settlement date, it would take more than five days to cover all short positions.

This semiconductor giant was among the stocks pushing markets to new highs earlier this month. Its shares ended the short interest period with more than a 4% gain, and they have continued to climb since then. The stock closed most recent at $40.95 a share, after hitting a 52-week high of $41.05 earlier in the day. The 52-week low is $33.23. The share price is nearly 13% higher than at the beginning of the year.