Last week, the defence ministry of Argentina signed a letter of intent to buy light and medium utility helicopters from Hindustan Aeronautics Limited (HAL). This is a landmark for HAL, as well as for India, in terms of supplying military hardware to countries around the world. But the success has not come suddenly. To understand this better, take two simple numbers. The first is five times. That is how much the stock price of HAL has grown in the last five years. This has turned HAL into one of the highest valued public sector enterprises in India today. Its market...