[adampepp]

Sanjay,

UNH has classic "Network" moat in which customers benefit from the large network of available doctors, etc. Additionally, also because of its size, UNH has an economies of scale moat in which they can add additional clients at very low cost. Finally, most customers are locked in because of their employers, so there are high switching costs. This is a type of company in which an idiot could be CEO and they would still make money.

The biggest threat to their moat is government regulation which could interfere with their profitability. However, health care spends a ridiculous amount of money on lobbying, so it would be a long, drawn out process to get anything changed (with all the doctors associations, etc pulling different directions).

Adam