However, S&P has a discretionary rule: the Index Committee can add an acquirer of an S&P constituent in a stock deal even if eligibility isn't fully met, to cut turnover and maintain representativeness. This might be invoked if $SPCX was to take over $TSLA, for example.
SpaceX blocked from early US benchmark index entry as S&P reaffirms existing rules
Disclaimer: Investing carries risk. This is not financial advice. The above content should not be regarded as an offer, recommendation, or solicitation on acquiring or disposing of any financial products, any associated discussions, comments, or posts by author or other users should not be considered as such either. It is solely for general information purpose only, which does not consider your own investment objectives, financial situations or needs. TTM assumes no responsibility or warranty for the accuracy and completeness of the information, investors should do their own research and may seek professional advice before investing.

