Delta Air Lines Inc. (NYSE:DAL) has been added to the S&P 500 today in a surprise move. The airline’s shares jumped in value after the announcement was made, and the company was recognized as one of the most valuable in the world. The change will officially take effect today after the market closes.

Delta Air Lines

The addition of Delta Air Lines Inc. (NYSE:DAL) to the S&P 500 was not a complete surprise, but very few investors thought that Standard & Poor’s would make the decision so early. At time of writing shares, Delta Air Lines were up more than 9 percent for the days trading. Shares in the firm are trading close to their all-time high at the moment.

Delta performance

Delta Air Lines secured its face in the S&P 500 after massive growth in value over the last year. The company has seen its value increase by more than 130 percent in the last year, giving it a market capitalization of more than $18 billion. The company’s high valuation and the Standard & Poor’s decision to add more airlines to the S&P 500 led to today’s decision.

Delta Air Lines Inc. (NYSE:DAL) didn’t more than double in value by accident over the last twelve months. The company is expected to double 2011 earnings this year, and analysts do not expect the company to stop growing after that. Earnings for 2013 are expected to hit $2.80 pr share, while 2014 is expected to bring $3 per share to the company.

S&P 500 addition

Delta Air Lines Inc. (NYSE:DAL) will be a fully fledged member of the S&P 500 tomorrow morning when the market opens, and investors should expect more airlines to make the cut in the coming months. The S&P 500 list is the most important indicator of the health of the stock market, and the U.S. economy by proxy.

Because Delta Air Lines Inc. (NYSE:DAL) has been added to the index and the S&P 500 is used as a wide index, the company’s shares are likely to see more demand. Many investors and finds buy into the entire S&P 500 in order to see steady diversified gains. This afternoon and tomorrow morning many of those funds will be buying Delta Air Lines Inc. (NYSE:DAL) shares in order to keep in line with the S&P 500.