Southwest Airlines (LUV) - Get Report will begin pulling back its service to Cuba, with plans to end flights to two smaller cities on the island this September.

Southwest will operate its last flight to Varadero and Santa Clara on September 4, as the services are becoming too unsustainable, the company said.

The Dallas-based airline will continue its service from Fort Lauderdale and Tampa to the Cuban capital of Havana.

"Our decision to discontinue the other Cuba flights comes after an in-depth analysis of our performance over several months which confirmed that there is not a clear path to sustainability serving these markets, particularly with the continuing prohibition in U.S. law on tourism to Cuba for American citizens," said Steve Goldberg, Southwest Senior VP of ground operations.

What's Hot On TheStreet

The stock market may be overvalued: Now may be the time to pay extra attention to red-hot tech stocks such as Apple (AAPL) - Get Report and Facebook (FB) - Get Report. As TheStreet first reported Tuesday afternoon, asset valuations are somewhat "rich" by standard metrics, Federal Reserve Chair Janet Yellen said in London during a conversation about economic issues with British Academy President Lord Nicholas Stern. Yellen's comments on equity valuation and bank strength closely mirrored Fed Vice Chairman Stanley Fischer's from an IMF event held earlier in the day.

The iPhone has changed how you make money: TheStreet's Scott Gamm is out with a piece that will really get you thinking. Apple's iPhone will turn 10 years old on Thursday. The device not only turned Apple into one of the world's most valuable companies, helping to boost its stock price more than 700%, it also changed the way we invest and trade stocks Gamm points out.

In fact, the original iPhone -- and the current versions -- have an internal stocks app, allowing users to check the broader market indexes and individual stock prices. Having this in your pocket was a big deal 10 years ago.

"I think it's actually made the life for a typical investor much easier," Angelo Zino, an analyst with CFRA Research, told TheStreet. "I think they've been able to tap news flows much quicker."

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