The largest financial MCC950 Autophagy crisis in modern history. From the analysis of previous pandemics, we realize that the consequences of a pandemic are long-term. Economic markets all over the world responded having a sharp decline with all the Covid-19 outbreak along with a pretty rapid rebound to pre-crisis levels, resulting within a “V-shaped” movement in indices (e.g., S P 500), as opposed to the “U-shaped” movement during the GFC. Increased volatility and potentially extra integrated capital markets through the turmoil have negative implications for diversification opportunities. The influence from the Covid-19 crisis on the quantity of stocks in well-diversified portfolios must be additional investigated. Further research can also be warranted to examine no matter whether an expansionary monetary policy with historically low rates of interest in developed nations, which has boosted the economy and capital markets and, in specific, helped development stocks, which consist of most technology corporations, to attain larger cost Etiocholanolone Biological Activity multiples, has had a substantial impact on the quantity of stocks in well-diversified portfolios. 6. Conclusions This paper systematically analyses the diversification of equity threat using a dataset of 150 publications more than the period 1952 to 2021. The framework used within this article to evaluation study on the optimal quantity of stocks that make up a well-diversified portfolio shows the depth and complexity from the subject itself, also as the numerous associated connections. Based on the in depth overview in the optimal portfolio diversification we can identify various directions for future study. 1st, after a thorough analysis of each of the studies,J. Threat Financial Manag. 2021, 14,24 ofit might be concluded that an optimal quantity of stocks that constitute a well-diversified portfolio does not exist for whatever industry, period nor investor. This function has proved that evaluating the amount of assets which result in optimal diversification will not be a simple process as it is impacted by a huge quantity of unique things: the way systematic risk is measured; the investment universe (size, asset classes, attributes of the asset classes); the investor’s qualities; the transform over time with the assets features; the model adopted to measure diversification (i.e., equally weighted versus an optimal allocation); the frequency of the information which is becoming utilised with each other with all the time horizon; circumstances in the marketplace that the study refers to. Among the issues with a lot literature concerning optimal portfolio diversification would be the selection of opinion on what’s thought of efficient diversification. More current evidence highlights that the size of a well-diversified portfolio is larger now in comparison to the previous research, which could mostly be brought on by reduced transaction expenses. This study further reveals that there was a considerable increase in the optimal quantity of stocks that constitute a well-diversified portfolio following thinking about a longer time period. An additional crucial getting of this study reveals that unsystematic danger has substantially elevated more than the final thirty years in the U.S. in comparison with the overall variability of your stock market place, which underscores the need for larger portfolios to lower diversifiable risk as a great deal as possible. As pointed out earlier, the identical portfolio size recommendation may not provide precisely the same level of diversification for many investors. This decision could be influenced by the frequency with the information, the threat measure made use of, the regional marketplace, the self-confidence level, the correla.