Take the hospital from the start of this Market Segment, and put it in the United States. It probably pays its staff through one of the suites below. Much of that software is written in India. The industry calls these suites human capital management, or HCM. Beside pay, they handle tax filing, benefits such as health insurance, and time and attendance: recording when each person works.

In Rippling's idea, the employee record is the root: payroll, benefits, the laptop, software access and the company credit card all follow from it.

The second tier serves America's mid-sized and small businesses. Each of these companies has chosen India for its engineering.

Two sell to, and through, professional employer organisations. A professional employer organisation, or PEO, becomes the legal employer of a small company's staff, and runs their payroll and benefits for it.

Four sell their payroll-and-HR platform directly to mid-sized employers:

Back to the hospital from the start of this Market Segment. Its nurses work in shifts. The hard problem is not paying them, but deciding who works when. The schedule has to match three things:

A shift schedule has to match a forecast of how busy each ward will be, the hours labour law allows each nurse to work, and the money set aside for wages.

• a forecast of how busy each ward will be
• the hours each nurse is allowed to work under labour law
• the money set aside for wages, called the labour budget

Every shop, restaurant and warehouse faces the same problem.

Both compete with UKG's Kronos products, the established name, in the first sub-segment.

Now picture the same hospital in Hyderabad. It pays its staff in rupees, under Indian tax rules, with provident fund and other deductions taken from each salary. The companies in this sub-segment pay India. Indian HR software is often called an HRMS, short for HR management system.