Stocks finished lower across the board on Wednesday as the World Bank revised its estimate for worldwide growth in 2014 from 3.2% to 2.8%. Shareholders in Exelon Corporation (NYSE:EXC), Delta Air Lines (NYSE:DAL), and Genworth Financial (NYSE:GNW) took the biggest hits of the day, however, ending as the worst performers in the entire S&P 500 Index (SNPINDEX:^GSPC). The S&P, for its part, lost 6 points, or 0.4%, to end at 1,943.

Utilities giant Exelon was the day's biggest laggard, losing 3.8%. While the utilities sector was also the worst-performing sector on Wednesday, Exelon added insult to injury when it announced a secondary share offering that will dilute its current shareholders. The money-raising efforts do in fact have a higher purpose: the funds will be used to finance Exelon's acquisition of fellow utilities giant Pepco Holdings, a move that will give the company unprecedented power in the sector.

Source: Delta Air Lines

Shares of Delta Air Lines shed 2.9% today, as the World Bank's dismal revision to global growth gave investors pause. The world's major airlines are dependent upon the health of economies across the world by definition; international travel will likely be impaired if foreign economies struggle to grow. On top of that, Germany's Lufthansa lowered its earnings forecast, giving Delta Air Lines investors more reason to worry as one of Europe's few economic powerhouses shows hints of weakness.

Finally, shares of Genworth Financial tumbled 2.8% on Wednesday. The life insurance company -- which also offers international mortgage insurance and other services -- isn't exactly known for its explosive sales growth. In 2009, in the absolute depths of the financial crisis, sales were $10.1 billion. Last year, Genworth Financial logged $9.4 billion in revenue. Normally, this sort of contraction would be extremely concerning, but patient shareholders have been amply rewarded as the business swung from a $460 million loss in 2009 to earnings of more than $570 million last year.