The stock was up more than 2 percent in afternoon trading.
In an earlier tweet Monday, Musk spoke out on the company's struggling China business. [I] "am very optimistic about Tesla's long term future in China, despite our earlier mistakes. Have great faith in the Tesla China team."
In February, Musk said the company would show off the Tesla home battery, a consumer battery for at home use, "fairly soon."
Analysts at Global Equities Research said the forthcoming announcement is "very likely" related a stationary battery for residential consumers.
Tesla "has been testing residential stationary batteries in about 200-250 households in California for about last 2 years," GER said in a note Monday.
Musk has often used the social media platform to share company news or hint at future developments.
Last week, Musk shot down apparent speculation that he uses tweets to influence the company's stock price. In a series of tweets, he said a short-term pop in the stock "does no good for Tesla or me... it would be wrong" to use social media to inflate stock price.
--CNBC's Jacob Pramuk contributed to this report.