S&P 500 investors face new risks as Spacex-Tesla merger, Anthropic IPO plans emerge

S&P 500 investors may face new risks as SpaceX-merger with Tesla and Anthropic's IPO plans emerge. The S&P 500 index fund helps investors spread their money across the largest US companies, but could see changes due to two major developments. SpaceX CEO Elon Musk hinted at a possible merger with Tesla during the company's Q3 earnings call last week, which if successful, could become the largest merger in history.

Anthropic, an AI company, filed an S-1 registration statement with the SEC, indicating its intention to go public, potentially leading to an IPO valuation of $1.5 trillion to $2 trillion.

These developments do not guarantee the companies' entry into S&P 500 index funds, as their inclusion depends on the index's rules and eligibility requirements. SpaceX would need to wait until June 2027 to be considered for inclusion. The potential merger's treatment in the index would depend on how the deal is structured and the number of shares available for public investors.

Investors holding S&P 500 index funds may gain exposure to SpaceX, Tesla or Anthropic if they become part of the index. However, this increased exposure could also lead to higher concentration risk, as nearly 40% of assets in a typical S&P 500 fund are currently invested in the index's top 10 holdings.