BPO services are generally categorized into horizontal and vertical services. These have been explained below:

1. Horizontal BPO: Horizontal BPO involves function centric outsourcing. The vendor specializes in carrying out particular functions across different industry domains. Examples of horizontal BPO are outsourcing in procurement, payroll processing, HR, facilities management and similar functions. Automatic Data Processing (ADP) is an example of a horizontal BPO vendor. ADP focuses on providing services in horizontal functions such as payroll, HR, benefit administration, tax solutions, etc. However, according to Gartner, companies should focus on providing vertical services as the market matures.
2. Vertical BPO: A vertical BPO focuses on proving various functional services in a limited number of industry domains. Healthcare, financial services, manufacturing and retail are examples of vertical BPO domains. EXL Service Holdings is a vertical BPO having focus on industry domains such as healthcare, business services, utilities and energy and manufacturing.

Table 1: Horizontal and Vertical BPO Source: BPO: The precursor of digital farms