Dividend checks continue to get fatter in Corporate America as more companies jack up their distribution rates.

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

We can start with FedEx (NYSE: FDX). The speedy parcel delivery company is boosting its quarterly dividend 8% to $0.14 a share. It's merely a coincidence that its FedEd Freight unit pushed through a 6.9% increase in its shipping rate a few days later.

UnitedHealth (NYSE: UNH) is also going for a healthier payout. The health-care coverage provider is prescribing a 30% increase to its distributions. Shareholders will now be receiving $0.2125 a share every three months. UnitedHealth also renewed its share repurchase program.

Umpqua Holdings (Nasdaq: UMPQ) is generating interest with its latest move. The Portland-based regional banker is jacking up its quarterly rate 29% to $0.09 a share. The move comes on top of a 40% hike last year. The moves have been substantial, but keep in mind that Umpqua was shelling out a quarterly dividend of $0.19 a share -- more than twice the new rate -- before slashing its payout to $0.05 a share in 2008.

Finally we have Iron Mountain (NYSE: IRM) on the move. The document storage specialist is growing its quarterly distributions by 8% to $0.27 a share. Iron Mountain is also moving to convert into a REIT, a tax-advantaged corporate structure that will result in even meatier dividends as it passes on at least 90% of its profitability to shareholders.

Checks and balances
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.

If you want to track these stocks to see if and when they hike their payouts again, consider adding them to MyWatchlist.