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's opening its wallet wider 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 over the past week.

We'll start with Speedway Motorsports (NYSE:TRK). The auto racetrack operator revved up its annual dividend to $0.34 a share. It's a good omen for the niche, with International Speedway (NASDAQ:ISCA) set to report its quarterly results on Thursday.

Investors who want to sink their teeth into a chewy dividend may warm up to DENTSPLY (NASDAQ:XRAY). The maker of dental office equipment -- including X-raying supplies, hence the ticker symbol -- is growing its quarterly payout by 11% to $0.05 a share. Look, Ma, no cavities!

NW Natural (NYSE:NWN) is another hiker. The natural gas utility company's quarterly disbursements are climbing 5% to $0.395. Investors aren't surprised. They've had decades of practice, since NW Natural has boosted its yield in each of the past 53 years.

Finally, we have MFA Mortgage Investments (NYSE:MFA) bringing home the bacon. Yes, even mortgage REITs can get in on the fun in this iffy environment. MFA specializes in high-quality, high-coupon, and adjustable mortgage-based securities. The company's new quarterly dividend of $0.22 a share is a 10% improvement over its previous rate. The move pushes up the yield to an eye-popping 16.2%.

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 is being recommended these days? Go ahead and give the newsletter service a shot with a 30-day trial subscription. Who knows? Maybe the next thing that will 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.