The code in the K button's Click event procedure in itself looks OK, but it's execution is conditional on the value of the unbound cboSymbolStock control in the form header. This control's RowSource property references two columns, PortfolioCode and Sergey, which don't exist in the Investments01_tbl table. You'll need to correct this.
The New Record button is navigating to an empty new record as expected. However, your extensive use of the LostFocus event procedures, as mentioned by arnelgp is causing problems if the user exits the control without entering any data. Generally speaking, the best place to validate data is the control's and/or form's BeforeUpdate event procedure. This includes a Cancel argument whose return value can be set to TRUE if the validation criteria are not met.
Some of the bound controls in the form seem to have the names of non-existent columns in the qryInvestments01_Sort01 query as their ControlSource properties. These ned to be corrected.