Last month, I predicted that U.S. auto sales would be very strong for the month of September, and that's exactly what we got yesterday, with the "big three" automakers all delivering double-digit growth. Fiat Chrysler (NYSE:FCAU) was the weakest of the three, with sales in-line to slightly below expectations, but notching 13.6% growth and making this the 66th month in a row of car sales growth for the company. GM (NYSE:GM) was the belle of the ball, just obliterating expectation with 12.5% growth versus the 7-8% expected by most in the industry. And finally Ford (NYSE:F) continues to be the fastest-growing of the big-three, growing a phenomenal 23% year over year for the month, while analysts were only expecting 19%. Going through Ford's sales data, we see that the increases in retail sales were broad based with passenger car sales up 15%, SUV sales up 23% and trucks up 29%. In fact, the retail vehicle sales numbers provided the company with its best September performance in 11 years. In addition, the F-series vehicles sales, which represent almost 1/3 of all vehicles sold and comprise the bulk of Ford's revenue, continued to accelerate from the strong results last month, increasing a whopping 16.4%, and serving as the key driver behind the truck segment's overall growth. Ford vans also reported phenomenal growth at 88%, making it the best September commercial van sales since 1987, and Ford SUV sales achieved the best September results in 12 years, making this the second month in a row the company has achieved this feat. I believe there are three key drivers behind Ford's and the other car manufactures' strong U.S. sales growth this month. The first is Labor Day. Or more specifically, the fact that Labor Day weekend was included in September this year, which is extremely rare, instead of being included in August sales as it normally is. This provided a huge, albeit one-time boost to this month's sales growth. This is an important point to keep in mind when looking at the results, as Labor Day weekend is a huge sales weekend for car manufacturers and dealers. The second key driver is low oil prices, which translate to low gas prices for consumers. Keep in mind, the average price per gallon is now $2.29 across the nation, as the energy sector continues to struggle with an oversupply of oil. As a result, we continue to see a large increase in sales specifically in the larger vehicle segments like pickup trucks and SUVs among all of the big-three, not just Ford. For example, Fiat Chrysler saw its Jeep brand lead the way with a 40% y/y increase for the month of September. Finally, ultra-low interest rates, mostly driven by the Federal Reserve's low interest rate policy, are also helping to drive U.S. sales, with financing so cheap what consumers are willing to stretch themselves. There was speculation the Federal Reserve would start to raise rates last month, but ultimately decided to keep them unchanged, continuing to provide a tailwind to the sector. Low rates and easier access to credit will continue to drive demand, as evidenced by a recent University of Michigan consumer sentiment poll that showed 28% of households surveyed believe it is a good time to buy a car because of low interest rates. Given all the positive numbers coming out of Ford for the past few months, investors have to wonder why the stock is not trading higher, but instead seems to be stuck around $14/share. All of the drivers I have listed above could be taken as negatives but when you think it through doesn't explain the stock's performance. For example, September got a one-time boost from the inclusion of Labor Day weekend, so the numbers could be (probably are) inflated. But looking back at August, Ford also crushed y/y growth expectations WITHOUT the holiday weekend sales, so we can be pretty confident in the trend. Cheap gas may be pushing sales of larger vehicles higher, but many analysts see oil prices remaining low for at least the medium term. Furthermore, consumers are paying less for gas not just because of cheaper oil, but also because the fuel efficiency on many larger vehicles allow them to get much better mileage. Finally, while interest rates cannot remain low forever, the Fed has been slow to raise them, and will do so gradually, especially after today's disappointing jobs report. One issue that could be dragging down the stock is international sales, especially China. Although Ford is not as huge in China, it does have a significant presence, and clearly growth is slowing in the Asian region, along with other emerging markets. However, Europe continues to improve, and may provide enough of a boost to offset this slowdown. And the U.S. market continues to be on fire. Overall, this was a stellar month for Ford sales, and the September auto sales rate was the highest in over a decade. Furthermore, the industry as a whole is potentially on track to beat its all-time record for total sales from 2000, with Ford well positioned to capture a significant portion of this growth. Yet the stock continues to trade around 15x earnings, and provides investors with a 4.5% dividend while they wait. I believe it is an attractive buying opportunity for opportunistic investors. More