.
I am not a business person and never learned business at university.
But my "naive" suggestion is as follows:
After 8 years of successful functioning, Lisa's business is worth 6 times $250,000, i.e. $1,500,000.
It means that the company's shares cost now $1,500,000, in total.
So, she could keep more than half in her possession and to sell the rest,
still remaining a major owner.
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If even me, without having any special education in the area, can solve this problem,
it means that its level of complexity is as 2 x 2 = 4, and everybody can solve it.
Do not understand, for what reason it was posted to the forum.
Only a smallest drop of common sense is needed for solving.