Space Exploration Technologies (SPCX -3.18%) closed at $118.24 per share on July 23 — down 48% from its all-time high of $225.64 per share from June 16 — which was the third trading session after its June 12 initial public offering (IPO).

However, several popular exchange-traded funds (ETFs) will continue buying SpaceX, even if its price keeps falling, because of their float-based weighting systems. The float is the number of shares available on the open market (in this case, the Nasdaq Stock Market) for public buying and selling. Float-based weighting systems will create substantial demand for SpaceX over the next several months as the float increases.

Here’s why investors need to be wary of SpaceX’s impact on the buying behavior of…