They have no control over it. But executives are dealing with an increasingly big headache when it comes to sales and profits this year: currencies.
For American multinationals that do business in developing markets, the wild gyrations and sharp currency declines make those earnings overseas worth less when they're brought back home and converted into dollars.
Proctor & Gamble gave us a preview of what to expect Wednesday.
The consumer goods company lowered its forecast for sales and profits for the year because of the sharp fall in the Venzuelan bolivar. P&G also said it's being hit by the devaluation of the Argentine peso and other emerging markets currencies.
It now predicts core earnings per share to grow 3 percent to 5 percent for the year, instead of 5 percent to 7 percent. It's expecting sales to come in flat to 2 percent higher, from a gain of 1 percent to 2 percent.
(Read more: P&G cuts outlook on emerging market currency outlook)
Venezuela devalued its currency last month for some products, including imported finished goods, from 6.3 bolivars per dollar to 11.36. That follows a 32 percent devaluation a year ago.
But this time, other currencies that are less controlled by governments and central banks are falling sharply as well. A variety of factors are causing the selloff, including domestic economic and political problems, as well as effects from the Federal Reserve's tapering of monetary stimulus.
As a result, analysts said P&G isn't the only company in the currency crosshairs.
"We remind investors that neither Clorox, Colgate or Energizer had included a devaluation of the bolivar in their guidance," said Nik Modi of RBC Capital Markets. "We believe these companies may follow suit in the near future and update their outlook for changes in the exchange rate in Venezuela."
(Read more: P&G provides protection in down market: Pro)
In a research note, BMO Capital Markets' Connie Maneaty added Tupperware, Estée Lauder, and Newell Rubbermaid to the list of companies at risk of getting hit by currency swings.
(Read more: Are emerging market firms the real worry?)
Bernstein Research's Ali Dibadj looked at consumer companies with the most exposure to Venezuela as a percentage of total sales and found that Avon and Colgate-Palmolive are the most exposed, with more than 4 percent of sales coming from Venezuela.
On Thursday, Avon cited slowed business in emerging markets as a contributor to its its fourth-quarter revenue decline.
(Read more: Avon: Bribe settlement could reach $132M)
The bottom line: Currencies have been an unwelcome headwind, so be on the lookout for more companies to update and change their guidance.
—By CNBC's Sara Eisen. Follow her on Twitter @SaraEisen .
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