Tesla's Musk tells disgruntled shareholders: Buy Ford | Reuters

Investor relations by tweet

""We expect that as companies make the transition to publicly-traded status, the governance structures and practices in place at the time of the IPO will evolve to align with the company's changing strategy," the letter reads. "However, Tesla's seven-member board is largely unchanged from its pre-IPO days."

Led by the enigmatic Musk, Tesla recently became the most valuable U.S. car company, passing General Motors Co (GM.N) for the top spot.

Tesla's market value has since slipped to just shy of GM's. As of Wednesday, the market cap of the Silicon Valley automaker was $50.3 billion, while GM's was $50.8 billion.

"This investor group should buy Ford stock," Musk posted on Twitter on Wednesday afternoon. "Their governance is amazing..."

Musk then said on Twitter that he would follow up soon on an earlier promise to appoint more independent directors, "but this (investor) group has nothing to do with it.""

Tesla's Musk tells disgruntled shareholders: Buy Ford | Reuters