This depends on the circumstances. As a general rule, you may speak about a company that is a customer or supplier of your employer, provided that you and your company have no confidentiality agreement with that customer or supplier and you do not disclose any information given to your company in confidence. However, you may not discuss your employer or confidential information concerning its relationship with the customer or supplier, such as your employer’s purchases from a supplier or orders from a customer. To be safe, if you are unsure whether information is confidential or otherwise restricted, you may not disclose it.