The date of execution and thus the actual transfer of ownership of shares in the case of a share deal or of assets in the case of an asset deal is referred to as closing. Several weeks, or even months, may pass between signing and closing.
In contracts that contain conditions that must be satisfied after the agreement is signed and dated but before it can become effective, the closing date is sometimes referred to as the date when these conditions precedent are satisfied and the transactions contemplated by the agreement are finally completed.
The articles of association and shareholders' agreement may also specify that existing shareholders have the right of first refusal when a shareholder wishes to sell their shares. This means the shares must be offered to existing shareholders before they can be sold to anyone else.
Identify your letter as a letter of intent to sell shares. Define the company and who is meant by "seller" and "buyer." Include contact information for all the parties. Include the postal and registered address of the company, if they're different. Name every shareholder involved in the sale.