A number of analysts and investors, requesting anonymity, told Reuters that Musk's comments are adding to their concerns that his public statements are distracting him from Tesla's main business of producing electric cars. The stock sell-off knocked almost $2 billion (roughly Rs. 13,600 crores) off the company's market value.
Tesla shares closed at $310.10 (roughly Rs. 21,220) before rising 1.9 percent in after-hours trading.
James Anderson, a partner at Tesla's fourth-largest shareholder, asset manager Baillie Gifford, called the weekend's events "a regrettable instance" and said he had reiterated to the company the need for "peace and execution" of its core business.
The billionaire entrepreneur's spat with British diver Vernon Unsworth started last week, after rescue teams rejected Musk's offer of a mini-submarine created by his rocket company SpaceX to help rescue a 12-member soccer team and their coach trapped inside a flooded cave in the northern province of Chiang Rai.
"He can stick his submarine where it hurts," CNN reported Unsworth as saying. "It just has absolutely no chance of working."
Musk shot back on Sunday on Twitter: "We will make one (video) of the mini-sub/pod going all the way to Cave 5 no problemo. Sorry pedo guy, you really did ask for it." The tweet was later deleted.
Tesla spokespeople and lawyers did not respond to emails and phone calls from Reuters requesting comment on Musk's comments on Twitter.
Musk gave no evidence for alleging Unsworth was a paedophile. Unsworth said he would consider taking legal action against Musk over the remarks, in comments filmed in Chiang Rai on Monday by Australia's 9News. Reuters could not reach Unsworth for comment.
Unsworth's wife told Reuters on Monday that her husband was returning to Britain on July 19, where he will speak to lawyers.
Last week, Narongsak Osottanakorn, the leader of the rescue operation in Thailand, rejected Musk's mini-submarine as not suitable for the task. Musk responded on Twitter on July 10, calling Osottanakorn "not the subject matter expert."
Musk also regularly uses Twitter to criticise media reports on Tesla, which has struggled to meet its own production targets for its Model 3 sedan, which is seen as key to the company's profitability.
© Thomson Reuters 2018