When securities are provided to employees or directors, those employment-related securities may be subject to restrictions in order to incentivise the individual to remain with the employing company and meet certain performance conditions. The restrictions may affect the individual's ability to retain shares (for example, the articles of association may oblige an employee to transfer shares to 'permitted transferees' on the occurrence of certain events such as resignation), or the general rights attaching to the shares (for example, restrictions on transfer, dividend rights or voting rights). Very broadly, restrictions typically have the effect of reducing the market value of the securities (and therefore any income tax and National Insurance contributions (NICs) charge) upon acquisition. Where the restricted securities rules apply, further income tax (and possibly NICs) charges can arise on subsequent chargeable events, including the lifting, variation or expiry of the restrictions, or disposal of the restricted securities. However, it is possible for the director or employee