Gathering economic clouds point toward a second recession. Fortunately, investors can insulate their portfolios from this storm by investing in companies with recession-proof balance sheets. Here, we'll look at four such companies, and break down their balance sheets into two key components worth watching.

The cash component

Although it probably goes without saying, the more cash a company has going into a recession, the better. Witness the unprecedented cash hoards of Apple (Nasdaq: AAPL) , Microsoft (Nasdaq: MSFT) , Google (Nasdaq: GOOG) , and Intel (Nasdaq: INTC) :

Source: Yahoo! Finance.

At a bare minimum, a company should have at least enough cash or cash equivalents on hand to pay off all of its current liabilities -- a principle known as liquidity.

The most common measures of liquidity are the current and quick ratios. The current ratio divides a company's current assets (things like cash and inventory) by its current liabilities (expenses like salaries and rent). The quick ratio, on the other hand, simply excludes inventory from the preceding calculation because it isn't as easily convertible into cash. In either case, we want to see ratios higher than 1.

Company Current Ratio Quick Ratio Apple 1.75 1.71 Microsoft 2.60 2.56 Google 5.96 5.96 Intel 2.23 1.84

Source: RobotDough.com.

Not surprisingly, all of the companies from the preceding chart have more cash than necessary to cover their current liabilities. And if you include long-term investments, some of them have more than 10 times the amount they need!

The debt component

Debt is the yin to cash's yang going into a potential recession. It becomes exceedingly expensive to service as revenues decline, and it reduces borrowing power at the worst possible time.

In fairness, debt can be an unquestionably attractive and often necessary component of a well-managed balance sheet. Companies like Coca-Cola (NYSE: KO) and McDonald's (NYSE: MCD) , for example, regularly maintain debt on their balance sheets as a cheap form of financing. Their stable business models let them sustain this kind of capital structure.

As a result, you want to invest in companies with an appropriate amount of debt for their business. Enter the debt-to-equity ratio, which compares the amount a company owes to the amount it's actually worth.

Company Debt-to-Equity Ratio Apple 0 Microsoft 0.209 Google 0.075 Intel 0.042

Source: RobotDough.com.

If you convert this ratio into a percentage, you can relate it to concepts familiar to us as homeowners. Microsoft's debt equals to 21% of its equity. Intel and Google's debt, on the other hand, equals less than 4% and 8% of their respective equities. And Apple doesn't even register, because it has no debt whatsoever!

It's better to be safe than sorry

The exercises above show the financial strength of some of today's premier technology companies. Their large amounts of cash will help them better weather any financial storms that might be brewing. With the sector trading at its lowest P/E multiples in decades, investors seeking safety may want look into tech.