New Texas 100 Stock Index tracks state's big employers.

A major change has been made in the stock index that is used as an economic indicator by the Texas comptroller's office.

The new Texas 100 Stock Index tracks the price of the shares of the 100 publicly-traded companies in the state that employs the most Texans. The most recent index reflects how much an investment of $1 in each company made in December 1997 would be worth a year later.

The old stock index tracked the monthly prices of 46 publicly traded companies with headquarters in Texas. The new stock index contains 13 companies that were in the old index.

"While there is some overlap between the old and the new stock indexes, the small amount of common entries indicates that many of the components of the old stock index were …