Elon Musk appears to now officially have Goldman Sachs Group Inc. (GS.N) on board.

Goldman Sachs put out a notice to clients Wednesday saying it was acting as a financial adviser “in connection with a matter that is fundamental” to Tesla Inc.’s (TSLA.O) value and removed its research analysts’ rating on the automaker. Andrew Williams, a spokesman for the bank, confirmed the notice and declined to comment further.

The notice comes two days after Musk tweeted he was working with the bank and private equity firm Silver Lake as financial advisers on his plan to take Tesla private. Goldman Sachs hadn’t officially signed on at the time of the tweet, Bloomberg News reported Tuesday.

Tesla shares dropped Wednesday as the U.S. Securities and Exchange Commission sent a subpoena to the electric car-maker regarding Musk’s plans to take it private and his claim to have had “funding secured” for the deal. The stock was down 3 per cent at US$337.21 at 1 p.m. New York time after falling as much as 4.5 percent.