Safety is a relative concept in the stock market. No matter how well established it is, every business is vulnerable to things like economic recessions, quality control crises, and accounting scandals. These issues don't typically arise with much warning, so investors must be willing to take on some degree of risk when owning a stock.

Yet there are companies that offer unusually high levels of safety thanks to a combination of stable sales and ample cash savings. A steadily growing dividend also helps protect returns while calming investor worries about a cash crunch impacting the business. Procter & Gamble (PG 1.27%) and Coca-Cola (KO 0.46%) easily fit in this category. Let's look at a few reasons why you might want to add these two ultra-safe dividend stocks to your portfolio today.

1. Procter & Gamble

Procter & Gamble could be the definition of an ultra-safe stock. It dominates dozens of consumer staples categories ranging from laundry care to healthcare and diapers to detergent. That massive global sales base protects shareholders from a regional downturn, and P&G's focus on essentials means that demand won't collapse even during a sharp recession.

The dividend giant is also highly profitable. Operating profit margin is nearly 10 percentage points higher than rival Kimberly-Clark's 15% margin. Procter & Gamble also turns nearly all of its earnings into free cash flow, which helps explain how it can so easily afford to boost its dividend with each passing year.

Investors can set their clocks by that dividend hike announcement, too. P&G has paid a dividend every year since 1890 and has raised the payout in each of the last 67 years. This past April's increase was 3% and expanding earnings in 2023 could support a slightly bigger boost early next year.

2. Coca-Cola

There's no doubt that on-the-go beverage preferences will change over the next few decades. However, investors can feel just as assured that Coca-Cola will play a key role in the global industry over that time.

Consider its latest earnings results as an example of how well Coke can perform in a difficult selling environment. Organic sales were up 11% this past quarter thanks to a healthy mix of rising prices and higher volumes. The company is seeing strong demand for its core soda brands, but even better demand for non-traditional niches like energy and sports drinks.

Its finances are impeccable, with industry-leading profit margin, cash flow, and return on invested capital. These wins make it highly likely that shareholders will see steadily rising returns through a combination of higher annual earnings and a growing dividend. Coke has raised its dividend for 60 consecutive years and the stock currently yields over 3%.

Wall Street concerns about slowing growth have kept its shares trailing the wider market in 2023. However, investors with longer time horizons can ignore that short-term volatility and focus instead on Coke's bright future, which likely includes steady market share gains and expanding profits.

Like P&G, Coke's brand could take a hit from a quality control misstep or any number of unforeseen crises. But, as stocks go, these blue chip giants are among the safest an income investor can choose to own.