OOH Holdings Limited is an investment holding company. The Company is engaged in the provision of advertising display services in Hong Kong. The Company's segments include Transportation Business and Healthcare Business. The Transportation Business segment is engaged in the provision of advertising display services over the transportation media platforms. The Healthcare Business segment is engaged in the provision of advertising display services over the healthcare media platforms. The Company is out-of-home advertising space and service provider in Hong Kong, with a focus on advertising on minibuses, hospitals, clinics and health and beauty retail stores. It provides out-of-home advertising spaces and services to its customers, which include direct advertisers aiming to promote their brands, products or services, and advertising agents acting for such advertisers. The Company offers its customers design and production, advertisement logistics, installation and dismantling services.