Elon Musk’s fortune has suffered a major decline after shares of his space company, SpaceX, extended their sharp sell-off, wiping an estimated $350 billion from his wealth within a week.

The decline followed a steep fall in SpaceX’s stock price after the company’s strong market debut, which had briefly pushed its valuation close to $3 trillion and helped make Musk the world’s first trillionaire.

SpaceX shares fell further on Tuesday, continuing a three-session decline that erased more than $600 billion in market value and pushed the company’s valuation closer to $2 trillion.

The sell-off was triggered by investor concerns over SpaceX’s valuation, increased spending plans, debt obligations, and broader weakness across technology stocks.

The company’s plans to raise billions through debt issuance to support expansion efforts have also added pressure on investor sentiment.