Updates with Tesla Motors earnings.

(FIT) - Get Report fell by 8.6% Tuesday, closing at $37.26, after the San Francisco maker of wearable fitness devices announced a large secondary stock sale Monday night, shortly after the company reported third-quarter earnings and revenue that beat expectations.

Fitbit said it will offer 21 million shares in the stock offering. The company plans to sell seven million of its own shares and 14 million from existing shareholders. Fitbit said lockup restrictions for 2.3 million shares will expire on Wednesday.

Fitbit said the proceeds will be used for several corporate purposes, including research and development. But Wall Street was not pleased by news of the stock offering.

Read TheStreet'sreport on why Fitbit shares dropped on Tuesday.

Brad Erickson, an analyst at Pacific Crest Securities, called the stock sale "curiously timed," according to a report by the Wall Street Journal.

But Erickson said "any volatility it's causing in the shares is likely to be short lived," the Journal reported. He added that demand for Fitbit's fitness trackers remain strong.

TheStreet's Jim Cramer, appearing on CNBC's "Squawk on the Street," said he has one big concern about Fitbit.

"Is this the wellness tool of the future or is it GoPro (GPRO) - Get Report?" Cramer asked. "And that's what everyone fears; that it's just another GoPro." GoPro shares have declined sharply this year.

After the closing bell on Monday, Fitbit reported better-than-expected quarterly earnings and revenue for its third quarter.

Fitbit said it earned 24 cents a share for the quarter, above analysts' estimates of 10 cents a share for the quarter. The company reported revenue of $409 million for the third quarter, a 168% increase from the year-ago quarter, and above analysts' estimates of $350.97 million.

Fitbit was taken public this past June. Priced at $20 per share for its IPO, Fitbit surged by about 50% on its first trading day, closing at $29.68.

Shares of Tesla Motors (TSLA) - Get Report  jumped by 11% in after-hours trading Tuesday after the electric car maker said it delivered more cars in the third quarter than it anticipated. It also said total sales rose by 10% to $936.8 million.

The company delivered 11,603 vehicles in the three-month period, 23 more than it said it would.

But Tesla's losses increased to $229.9 million, or $1.78 per share, in the quarter from $74.7 million, or 60 cents per share, in the comparable period of 2014.

Read TheStreet'sreport on Telsa's quarterly earnings.

The company's shares closed at $208.35 Tuesday, down by 2.5% during the regular trading session.

Sprint (S) - Get Report dropped by 7% Tuesday, closing at $4.50 after the nation's fourth-largest wireless carrier reported disappointing earnings.

Sprint said its fiscal second-quarter loss widened from a year earlier to 15 cents a share from 1 cent a share a year earlier. Analysts had expected a net loss of 7 cents. Sprint generated revenue of $7.98 billion, below estimates of $8.12 billion.

However, wireless net additions rose significantly as promotional efforts paid off. Additions jumped 1.06 million, up from 675,000 a year earlier.

The company previously announced plans to cut an unspecified number of jobs and eliminate outside hiring as it pares $2 billion in expenses.

"We have a very clear plan to return Sprint to profitability," company CEO Marcelo Claure said in a telephone interview Tuesday with Re/code. "That's the next big task; that hasn't happened in 11 years," Claure said.

Twitter (TWTR) - Get Report CEO Jack Dorsey is making another change at the micro-blogging site, just a few weeks into his new job.

Twitter users will now be "liking" tweets instead "favorite-ing" them, and they'll be using a heart button to show their approval instead of a star. Read TheStreet'sreport.

Twitter shares closed at $29.13, a decline of less than 1%.

Shares of Alphabet (GOOGL) - Get Report closed at $748.82, up a fraction of a percentage point, after company CEO Larry Page discussed his firm's relatively new corporate structure Monday night.

In a Q&A session with Fortune editor Alan Murray at an event in San Francisco, Page said the company would operate somewhat similarly to Warren Buffet's Berkshire Hathaway (BRK.A) - Get Report , according to Reuters.

Read TheStreet's full report about what Page said.

Separately, the company once known as Google said it plans to begin drone package deliveries in two years, Reutersreported.

At a media event Tuesday in San Francisco, Intel (INTC) - Get Report unveiled its Internet of Things strategy, according to a report by the San Jose Mercury News.

Intel is delivering "a comprehensive set of building blocks with a strong ecosystem to address the IoT opportunity," said Doug Davis, senior vice president in Intel's IoT Group, according to the newspaper. Intel shares rose by less than 1%, closing at $34.31.

Starting today, Sling TV's live and on-demand Internet TV app for Android and iOS devices supports Google's Chromecast.

"Sling TV fans have made it clear since the beginning that Chromecast is a must-have device, and we agree," said Roger Lynch, CEO of Sling TV. "With Chromecast, Sling TV customers now have the ability to move their entertainment experience from their mobile device to the big screen seamlessly."

Sling TV currently supports Chromecast on Android smartphones and tablets, iPhones and iPads. Compatibility for Windows and Mac laptops is coming soon, the company said.

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.