Investment scheme created by Egyptians (7)

I believe the answer is:

pyramid

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'investment' is the definition.
(I know that pyramid is a type of speculation)

I can't explain the remainder of the clue.

Can you help me to learn more?

(Other definitions for pyramid that I've seen before include "hierarchical organisation" , "Giza monument" , "Monumental Egyptian structure" , "Egyptian edifice" , "Egyptian landmark" .)

I've seen this clue in The Daily Express.

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