Any investment in a company should not be made in isolation. Instead, it should be in conjunction with each piece of the portfolio to understand its overall and net impact on various correlations and performance ratios. Further, it is important to avoid excessive concentration in any single position, sector or company and restrict any investment to 5-10% of the portfolio value to de-risk any substantial impacts on the rest of the holdings. Based on these factors, investors can hone in on an appropriate dollar amount and work backwards from there to acquire the requisite number of shares.