The Dow Jones Industrials (DJINDICES:^DJI) lost just under a hundred points this week, dropping from the record levels where it started the week as investors worried about the possibility that the coming second-quarter earnings season won't go as well as companies hope. Despite relatively benign news during the week, DuPont (NYSE:DD), Boeing (NYSE:BA), and ExxonMobil (NYSE:XOM) posted the worst losses among Dow stocks over the past five trading sessions.

Source: DuPont.

DuPont dropped more than 4%, with nearly all of the losses coming on Friday after the chemical and agricultural-productivity company issued a dire earnings warning. Blaming an unexpected drop in demand for corn as farmers gravitated toward planting more soybeans, DuPont said that its earnings per share for the full year would come in $0.20 to $0.35 lower than anticipated, with a new range of $4 to $4.10 per share falling well short of where most shareholders expected to see the chemical company's results. Given the extent of the decline, investors are clearly worried that this is more than a one-time event, yet if DuPont can avoid duplicating the mistake next year, then the damage could be far less in the long run than today's share-price plunge would suggest.

Source: Boeing.

Boeing fell almost 3%, with declines coming steadily throughout the first part of the week. Most of the discussion about Boeing this week came in connection with the coming debate on reauthorization of the U.S. Export-Import Bank, which provides funding to foreign nations seeking to make major purchases of high-ticket items like aircraft. Boeing has historically benefited a great deal from the existence of the Export-Import Bank, and if the entity doesn't get reauthorization from Congress, then it could potentially cost the aircraft manufacturer more than $10 billion in sales, assuming would-be buyers can't find financing elsewhere. Commercial customers have largely been able to support Boeing's stellar growth recently, but nevertheless, losing the Export-Import Bank would be a sizable blow to Boeing's future prospects.

ExxonMobil declined 2.5% on an eventful week in the energy industry. News that the U.S. government had opened up export of crude oil turned out to be somewhat overstated, with the specific authorization allowing just two companies to send a limited amount of processed energy products overseas. Nevertheless, refinery stocks plunged across the board, and given the importance of Exxon's downstream operations as part of its overall business, the Dow energy stock felt the negative impact as well. At this point, the week's refining-led declines seem overblown, but it remains to be seen how the U.S. will react in the future to further attempts to open up crude-oil trade to international buyers.