Shares of the electric car maker ended the day at $377.64, up $11.41.
Musk announced Wednesday that the company's "unreal" semi-truck was tentatively set to be unveiled in October.
Musk had said earlier this year the semi would be introduced in September.
Musk has also already revealed some details about the project. Speaking at Tesla's annual shareholder meeting in June, the CEO said the automaker has been working with its "biggest customers" on the design of the semi-truck, so they already know what the Tesla is making.
"They want to know how many can they buy, and how soon," Musk said at the time. He also said he "really recommend[s]" people show up for the unveiling, adding that "maybe there is a little more than we are saying here."
The truck could be a profitable move for Tesla in the long term, particularly if it utilizes automation or autonomous driving technology, Oppenheimer analyst Colin Rusch said on CNBC's "Power Lunch" on Thursday.
"I think it is part of the core strategy for the company here," Rusch said, "As we look at where there is real value to be extracted from the transportation market, it is really in driver safety, driver performance, and the value of those drivers. So if you are able to automate some of that drive time and eliminate some of the labor, there is a real savings there to be had."
Rusch added that the potential market for semi-cab trucks in North America, where Tesla's vehicle would compete, is worth as much as $30 million.
However, as the company enters a new market, Rusch worries about Tesla's ability to execute on all of its various businesses and generate free cash flow.
Still, the fact that Cummins and Daimler are already investing in building platforms for electric semi-trucks indicates there may be opportunity in this technology.