DETROIT — Shares of Tesla Motors Inc. and SolarCity Corp. rose Monday after the head of both companies said they won’t have to raise money this year.

Elon Musk tweeted over the weekend that the money-losing companies won’t need to raise equity or corporate debt in the fourth quarter despite a proposed merger and other potentially costly moves.

Musk said Tesla will introduce a new product on Oct. 17. Its lower-cost Model 3 is also due out next year.

Musk — who is the chairman of SolarCity and the CEO of Tesla — proposed in June that Tesla acquire SolarCity. Shareholders must still vote on the merger, which has been delayed by multiple lawsuits.

Tesla shares rose 2.2 percent to close Monday at $200.95. SolarCity gained 4.9 percent to $19.59.