It is always acceptable in business to show your appreciation when management recognises your efforts and achievement. Writing a thank you note for a promotion can indicate to your boss that you value your position in the company. It also can be a chance to reiterate your willingness and commitment to continue to meet goals and expand in your current position.
Send the note soon after the promotion was given. Timeliness is key in thank you notes. Within a few days of formally receiving a promotion, send a thank you note to your boss to show your appreciation.
Hand write the thank you note. Notes that are handwritten have more personal meaning and show more forethought than an e-mail that is sent through normal office channels. Write legibly in the note. If your handwriting is hard to read, typing the note is acceptable, but an actual note card is still recommended.
Stay professional in the note to your boss. Write the letter in a way you would feel comfortable if it were showcased to other employees in the office. Begin the note with a greeting to your boss using the name you have been instructed to call him. Do not be more or less formal than you would be in a normal business situation. Express gratitude for the promotion and the recognition of your efforts in your position. Briefly state your excitement to continue to provide excellent work for the company. End the note with a professional closing and sign your name.
Avoid giving gifts with a monetary value. A simple thank you note is sufficient.