Features of diversification and formation of individual parts of the securities portfolio, as well as the parameters of bringing it to the planned parameters have a significant impact on investment efficiency and risk. The urgency of rebalancing the securities portfolio in the activities of investment funds has been clarified, as such entities often have a certain policy on the structure of assets and liabilities. The aim of the work is to clarify the features of rebalancing the securities portfolio, which ensure the optimal parameters for the level of return on investment and risk. The need to rebalance the portfolio of securities in the long run due to the objective existence of the life cycle of companies, which determines the importance of timely sale of their shares. The connection between the peculiarities of rebalancing the securities portfolio and the issues of its risk and efficiency is clarified. Features of different types of such rebalancing from the point of view of influence on balance of risk and efficiency are considered. No type of rebalancing can achieve both risk minimization and efficiency maximization. The classification of types of corresponding rebalancing is carried out. The optimality of the type of rebalancing of the securities portfolio depending on the market features is specified: speculative or investments; and the impact of taxation on the intensity of asset purchase and sale transactions was defined. The main disadvantage of this type of rebalancing as profit-taking is a significant increase in taxes and deterioration of the portfolio structure due to the sale of assets, which are constantly rising in price and purchase of bad assets. This type of rebalancing is not optimal for markets (e.g., the US) and stocks that are constantly rising in price, but is appropriate for speculative volatile markets (e.g., China and East Asia) and assets. The main alternative to this type of rebalancing is to record losses or follow a certain index. An example of the practical use of this type is the Vanguard S&P 500 ETF, which completely repeats the structure of the S&P 500 stock index while buying stocks that rise in price and sells, on the contrary, decreased. This type of rebalancing of the securities portfolio is considered optimal for emerging markets and stocks. An alternative to these two types of rebalancing is one that involves the sale of assets only in the event of a loss of fundamental attractiveness. The change of portfolio shares is carried out by purchasing additional assets upon receipt or appearance of cash. However, this almost eliminates the targets of diversification in terms of risk management. Criteria for determining the stage of aging of the company and the time of sale of its shares are proposed. It has been established that holding bonds in a portfolio in order to provide a reserve for acquiring shares at the time of their price fall is advisable only when expecting a nonsystemic crisis, that is, a crisis for an individual asset; in the activities of investment management institutions, the type of rebalancing of the securities portfolio should be a secondary issue, as the economic basis for their economic efficiency in the long run is the selection, purchase and holding of fundamentally attractive shares.