It just depends on whether the 4-fold increase in share price accurately reflects an increase in the Real Value of the business concerned or whether it only relects an increase in the Perceived Value or Expected Future Value of the business.
Any increase in Real Value will be evidenced by a commensurate objective increase in the productivity of the business, according to however productivity is measured in that particular industry.
An increase in share price solely based on an increase in Perceived Value, which is unsupported, within a timeframe recognised and accepted within that industry, by any increase in Real Value will in due course be followed by a commensuarte reduction in Perceived Value and hence, share price.