Consumers know how hard it is to resist borrowing money. Companies face the same temptation, if not more so, especially with rivals leveraging up and taking advantage of low-interest rate loans.

Yet, there are still 26 non-financial companies in the Standard & Poors 500 index, including social media company Facebook. payments processor Visa and accessory seller Michael Kors that ended the first calendar quarters reporting no long-term debt.

Some of these companies might have other financial obligations, such as long-term leases for retail space or other equipment or short-term loans to be paid off within a year. But this analysis measures what accountants call long-term debt, or financial obligations due in more than a year, which leaves out short-term bridge loans thats not debt the company is planning to lean on for long. Most of the companies dont have short-term debt, either.

Resisting debt is especially difficult for companies with interest rates as low as they are now. Companies with the top credit ratings are able to borrow for just 1.5 percentage points over the rates on Treasuries with similar maturities.

Thats a downright bargain if you consider that such corporate bonds have gone for 1.7 percentage points higher than Treasuries the past year and nearly 2 percentage points higher than Treasuries over the past five years.

And low rates explain, in part, why many companies are increasing their long-term debt. Companies in the S&P 500 reported a 10% increase in long-term debt in the most recent calendar quarter compared with the same year-ago period.

Making it even hard to avoid borrowing: investors are punishing companies that dont have long-term debt, at least this year so far. An equal-weighted index of the debt-free S&P 500 companies is down 0.3% this year, trailing the 4.4% gain of the S&P 500 at large.

Investors often applaud companies that lever up during times credit is plentiful. Increasing debt allows companies to boost their returns relative to the stock invested in the company, which pleases stock investors. But these same companies often punish indebted companies when the credit markets tighten and interest rates rise.

Facebook is the most valuable company to carry no debt. The Internet company doesnt have a situation like many international tech giants, which have been borrowing money so they can pay U.S. investors cash dividends while keeping cash stashed overseas away from Uncle Sam.

Some companies have also cut their long-term debt to zero recently. A year ago, accessory maker Coach was carrying a very small amount of long-term debt: $485,000. That was reduced to zero as of the first quarter ended March 29, 2014.

But all the same, other companies have recently added long-term debt, too. Computer software company Citrix was debt free in the first calendar quarter, but on April 25, 2014 announced it sold $1.3 billion long-term notes.

When investors get more cautious than they are now, they tend to reward companies more for financial conservatism. That was the case last year. The no-debt companies, for instance, saw their stocks rise 20% over the past twelve months, beating the 15% gain of the S&P 500.

To be sure, theres no immediate concern about the level of debt held by companies in the S&P 500. Nearly 90% of the companies in the S&P 500 with debt are giving the highest investment grade credit ratings from agency Standard & Poors. And 80% of the companies in the S&P 500 have stable ratings outlooks, meaning theyre not likely to be downgraded in the near future, says S&P.

And while debt held by companies in the S&P 500 rose 9% in 2013, cash balances also shot up, S&P says. That means the net debt, or debt minus cash, only increased a less severe 4.7% in 2013, S&P says.

Yet if, or when, investors get nervous about the state of the economy, or the credit markets, these companies debt-free might again be glad they kept long-term debt off their books.

Below are the companies in the S&P 500 that report $0 long-term debt: