Pension funds pools’ investments have an impact on its growth. These investments can be either in equity stock, bonds, deposits, or in other miscellaneous assets that can generate different results with the involvement of some endogenous factors such as rate of return, inflation etc. To bring out the core investment factors determining pension fund growth, a stepwise regression technique was used on a dynamic panel data model. Moreover, to check the individual significance of the included variables in the model progressively, R2-change was observed. This study has found that the investment factors behave positively in high growth-oriented OECD economies and have a negative impact in low growth-oriented countries. Moreover, pension funds growth is slower due to market volatility in low-growth oriented economies. The study helps to know the utilization or investment factors that support the large asset-holding of financial-sector of OECD economies.