I love to kick off the new trading week by taking a quick peek at companies that have just hiked their dividends. It's not just about the money. A company that is easing up on its pocketbook probably has improving fundamentals to back up that generosity.

Readers of the Income Investor newsletter can certainly appreciate that kind of thinking. Let's take a closer look at four of the companies that inched their payouts higher this past week.

We can start with Cintas (NASDAQ:CTAS). The uniform-leasing giant boosted its annual dividend by 11%, to $0.39 a share. Yearly hikes have become a dependable trait of the company since it went public in 1983. Overall, Cintas has grown its distributions at a compound annual rate of 21%. Yes, that uniform looks custom-tailored for income investors.

Merrill Lynch (NYSE:MER) also upgraded its payout. Things have been going well for the investment bankers and full-service brokers as a whole, and Merrill Lynch is no exception. It's kicking some of its newfound wealth back to shareholders with a healthy 40% spike in its dividend rate. Investors will now be receiving $0.35 every three months.

Valero (NYSE:VLO) was another gusher. There's nothing crude about the company's new $0.12-a-share quarterly dividend, boosted from the previous $0.08 per share. At 50%, it's the largest dividend increase in history for North America's largest refiner.

Finally, aluminum titan Alcoa (NYSE:AA) put the pedal to the metal with its first hike in six years. Along with an ambitious share-buyback plan, Alcoa announced a 13% improvement in its quarterly distribution rate, to $0.17 a share.

Subscribers to the Income Investor newsletter can appreciate the companies sending more and more money to their investors. The newsletter singles out companies that are committed to growing their distributions with market-thumping results.

Want to see what the Fool is recommending these days? Go ahead and give the newsletter service a shot with a 30-day trial subscription. Who knows? Maybe the next thing to get hiked will be your interest.

Longtime Fool contributor Rick Munarriz pays attention to yield signs. He does not own shares in any of the companies in this story. He is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.