The month of May was a little bumpy for Ford Motor Company (NYSE:F). Former CEO Mark Fields was ousted toward the end of the month, replaced by Jim Hackett. That was followed by a massive shake-up in Ford's upper management in an attempt to cut slack from the automaker's bureaucratic practices. After that, investors looked toward the company's May sales results in hopes for something positive. Here are three key takeaways from the data.

Fleet, retail, and inventory

In total, Ford's U.S. sales were up 2.2% to 241,126 units, but it's fair to note that an increase in fleet sales, rather than retail sales, helped push the results above last May's comparison. Ford's fleet sales were up 8.4% to 82,844 units, compared to a 0.8% decline in retail sales, down to 158,282 units.

Overall, Ford's fleet sales generated 34.4% of total sales, which was 200 basis points higher than the prior year's figure, and far higher than General Motors' (NYSE:GM) 19.4% during May. Furthermore, that increase was driven by a 270-basis-point increase in daily rental fleet sales, generally the least desirable type of fleet sale. Similarly to last year, Ford's fleet sales volume is going to be higher during the first half of the year than the second half, but this is something to watch going forward.

Inventory was an industry concern a few months ago, but Ford's done a solid job selling down its inventory during the high-volume spring selling season. At the end of April, Ford's gross stock sat at 83 days' supply, and is already down to 72 days' supply at the end of May. Keeping inventory balanced is necessary to help keep a lid on incentive spending -- and Ford is doing nicely.

Rising transaction prices

Trucks and SUVs have been flying off dealer lots recently, while it's been getting harder and harder to push sales of cars higher. That held true again in May. Ford's truck sales were up a healthy 9.4% to 99,237 units, and its SUV sales were up 4.3% to 81,324. Those two segments combined to offset a 10% decline in car sales, down to 60,565 units. 

Three F-Series Super Duty trucks at a work site.

2016 F-Series Super Duty lineup. Image source: Ford Motor Company.

Ford's F-Series posted another incredible month: Sales topped 76,000, an increase of nearly 13% from the prior May result, and the pickup truck's best May result in 13 years. That's helping drive average transaction prices higher. "[W]e continued to see strong F-Series performance, with sales and share rising this year, along with average transaction pricing. In May, overall F-Series sales were up double digits and transaction prices grew $3,300 per truck," said Mark LaNeve, vice president for U.S. marketing, sales, and service.

Overall, Ford's average transaction prices increased $2,100 in May, which was much better than the overall industry increase of $500, according to vehicle sales data from J.D. Power's Power Information Network. While higher prices could have different long-term impacts, this is mostly great news for investors. 

Lincoln continues to roll

For long-term investors, Lincoln has long been a sore spot, with sales plunging from the brand's late-1990s peak. That trend has recently begun to turn around, and the premium lineup turned in another solid May result. Lincoln's sales increased nearly 5% in May, and remain up 5.8% for the calendar year, compared to the prior year. Better still, Lincoln's retail sales increased 9.7% last month, which marks the brand's 16th consecutive month of year-over-year sales gains.

The Lincoln MKC posted a strong May, with sales up 17% to 2,524 units, and the MKX posted strong total volumes, selling over 2,680 units. Now all eyes turn to the all-new Lincoln Navigator, which arrives in dealer showrooms later this year and could provide a sales boost if car buyers take to the larger SUV option.

Overall, it was a strong month from Ford as its 2.2% sales increase topped Kelley Blue Book estimates of a 1.2% decline. That's welcome news for investors after the management shake-up last month.

Daniel Miller owns shares of Ford and General Motors. The Motley Fool owns shares of and recommends Ford. The Motley Fool has a disclosure policy.