Venezuela has become so unfriendly to foreign companies that some of them have had to throw in the towel. Is it safe to own those that stick it out?
That's an important question for investors in many U.S.-listed companies with exposure to the South American country, which faces a combination of hyperinflation, a plunging currency and tumbling oil prices. Soaring materials costs — and an inability to raise prices — prompted Clorox to exit the country in September after 24 years. The departure was actually a relief for Clorox shareholders, given that the country was no longer profitable for the household products company.
Yet there are several other large U.S.-listed companies that make profits in Venezuela and are unlikely to leave anytime soon, barring an outright crisis. The key for investors is to understand just how much local-currency profits in Venezuela are really worth.
Read More Is Venezuela headed for a default?
One company that institutional investors are watching closely is MercadoLibre, which is essentially the eBay of Latin America. The Venezuelan currency has been revalued lower multiple times in the last few years and it can still be difficult to exchange bolivars for U.S. dollars, MercadoLibre's reporting currency.
But MercadoLibre has wisely decided to bite the bullet and adopt a more realistic exchange rate to reflect the value of its assets and revenue. That makes the chances of more bad news from MercadoLibre lower than in the case of other companies. MercadoLibre didn't respond to a request for comment from CNBC.
Here's how it works: For much of 2013, the company used a base exchange rate of 6.3 bolivars per U.S. dollar. But during the course of 2014, the company has adjusted the rate it uses to a far-more realistic level of roughly 50 bolivars per dollar. MercadoLibre said in a filing it has been "granted" U.S. dollars at the new exchange rate.
One clear impact of the change is that Venezuela is simply a smaller contributor to overall revenue, making it less of a worry. Venezuela accounted for 6 percent of MercadoLibre's revenue in the third quarter, down from 17 percent in the first quarter.
Read MoreVenezuela's future? 'Barbarity and people looting'
Even the 6 percent figure may exaggerate the importance of the country. In Venezuela, the company tends to sell a fair amount of autos, which have a lower profit margin than some other items. At the operating profit level, the contribution could be less.
What's more, MercadoLibre has so much growth in other regions that the Venezuela hit has turned out to be manageable. The company is expected to generate sales growth of 14.7 percent in 2014 and 18 percent growth in earnings before interest, taxes, depreciation, and amortization, according to consensus estimates in FactSet.
Other U.S.-listed companies could have more trouble dealing with the weak bolivar. Unlike MercadoLibre, some consumer companies continue to use exchange rates that are far stronger than what's available in reality.
Take iconic food company Kellogg, which continues to use the base exchange rate of 6.3 bolivars per dollar. If Kellogg were to adopt the more realistic exchange rate of 50 bolivars per dollar, the impact would be a roughly 87 percent decline in stated figures. Kellogg declined to comment to CNBC.
Read MoreCuba is Venezuela's biggest loser
How much would that hurt? In the nine months through September, Venezuela accounted for 2 percent of Kellogg's sales and 3 percent of its underlying operating profit. The company also had $100 million of assets in bolivars marked at the baseline exchange rate that would likely need a write-down if Kellogg adopted a weaker exchange rate.
It's important to remember that Kellogg needs any growth it can get. The company's sales are expected to fall 0.4 percent in 2014 and 0.8 percent in 2015. If revenue came in just a couple of percentage points lower as a result of Venezuela, it would be enough to hurt.
It's hard to predict what will happen in Venezuela, either in terms of its currency or the impact of depressed oil prices. But if Kellogg simply adjusted to a weaker exchange rate embraced by some more conservative companies, the pain might be immediate.