Good news for investors came when gross domestic product figures for the second quarter were announced on July 28: Americans started spending more during the spring months! More specifically, GDP increased at an annual rate of 2.6% during the second quarter, far higher than the first quarter's revised 1.2% growth.

Along with the upbeat economic data, earnings season is heating up with many companies reporting second-quarter results. Here are some of last week's highlights from companies making big moves or announcements.

It's about time!

One of the major stories last week came from Tesla (NASDAQ:TSLA): The company's long-awaited Model 3 was delivered to a handful of lucky employees. A lot rests on the success of the Model 3 as the company attempts to turn into a profitable automaker and distance itself from its cash-burning ways. The $35,000 Model 3 was designed for mass production, and management is aiming to hit a production rate of 20,000 per month by year-end before reaching its 500,000 annual target for 2018.

But the biggest question facing investors doesn't revolve around production numbers, at least not yet. The biggest question is: Will the masses pay a premium for an electric vehicle with fewer options and features than a traditional car? Generally, sedans in the U.S. sell for roughly $24,000, far cheaper than the starting price of the Model 3, which is presumably less than what most consumers will pay after adding premium options to the base model.

Tesla's Model 3

Image source: Tesla.

"One question for Model 3 reservation holders is: How much are they really willing to pay?" said David Whiston, an auto analyst with Morningstar, according to Bloomberg. "Thirty-five grand is going to get you a very basic model. The average Model 3 is going to be more like $42,000, and a fully loaded one will probably be in the $60s. It's not a mass-market car."

Ultimately, the Model 3's success or failure over the next 12 months will be absolutely defining for Tesla as the young automaker continues to be one of the most intriguing storylines in the automotive industry.

Blockbuster quarter

Shares of iRobot Corporation (NASDAQ:IRBT) were skyrocketing last week after the company released incredible second-quarter figures, announced an acquisition, and pushed guidance higher -- not a bad week's work. Going into the second-quarter results, investors were expecting a quarterly loss of $0.28 per share, so you can understand the tide of optimism when earnings per share checked in at $0.27. Even excluding a tax benefit that accounted for $0.15 per share, it was still a profitable surprise.

Not only did iRobot recently close on its Japanese distributor acquisition, but it announced also it had agreed to acquire its largest European distributor, Robopolis, for $141 million in cash. The transaction is expected to close in October. Management estimates the move will generate between $25 million and $35 million in incremental revenue this year but will dilute earnings by $0.30 to $0.45 per share before becoming accretive to earnings in 2018.

E-commerce king

Amazon.com (NASDAQ:AMZN) has thrived at the expense of traditional brick-and-mortar retailers, and that doesn't appear to be changing anytime soon with the amount of investment the online retail empire is pouring into building new warehouses, hiring engineers, and increasing delivery capacity. But that growth comes at a cost: The company missed analyst estimates by a long shot when it reported its second-quarter results on July 27.

Total revenue jumped an impressive 25% to $38 billion during the second quarter, topping estimates, but its net income of $197 million, or $0.40 per share, paled in comparison to the $1.41 consensus. The good news for investors is that, despite increasing costs, Amazon knows exactly what it's doing. 

"We are continuing to invest in businesses that will achieve four goals ... Customers love them, they can grow to be large, they have strong financial returns and they are durable and can last for decades," Chief Financial Officer Brian Olsavsky said on a media call, according to The Wall Street Journal. "That is, in essence, our investment philosophy."

Daniel Miller has no position in any stocks mentioned. The Motley Fool owns shares of and recommends Amazon, iRobot, and Tesla. The Motley Fool has a disclosure policy.