WASHINGTON (BLOOMBERG) - After the worst month for Tesla Inc shares in more than seven years, punctuated by company blog posts about the death of a Model X driver, billionaire entrepreneur Elon Musk is joking about his electric car-maker going bankrupt.

"Despite intense efforts to raise money, including a last-ditch mass sale of Easter Eggs, we are sad to report that Tesla has gone completely and totally bankrupt," the chief executive officer wrote in an April Fools' Day tweet on Sunday (April 1).

Another post included a photo of Mr Musk and a message that he "was found passed out against a Tesla Model 3, surrounded by 'Teslaquilla' bottles, the tracks of dried tears still visible on his cheeks".

Tesla's stock fell by 22 per cent in March, the steepest monthly drop since December 2010, the year the company went public.

Moody's Investors Service last week to cut Tesla's credit rating further into junk status and said the company may soon have to raise more than US$2 billion (S$2.62 billion), sending its bonds to all-time lows.