The St. Louis-based utility got its start in 1857 as the Laclede Gas Light Company.
Now it will be known as Spire.
Shareholders approved the name change officially on Thursday. It comes in the wake of two big acquisitions for the utility's holding company. The Laclede Group bought Missouri Gas Energy and Alabama Gas Corp. in 2014.
"Our new name unites our natural gas companies, better reflecting our growth and the company we have become," said Suzanne Sitherwood, president and CEO.
Spire will begin trading on the New York Stock Exchange on Friday under the ticker symbol. It serves about 1.5 million customers making it the fifth largest publicly traded natural gas company in the U.S. Laclede Gas serves about 630,000 customers.
The name transition for its utilities and subsidiaries, including Laclede Gas, will take place in 2017.
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