India is chasing China’s economy. Something is holding it back.

India’s economy is booming. Stock prices are through the roof, among the best performing in the world. The government’s investment in airports, bridges and roads, and clean-energy infrastructure is visible almost everywhere. India’s total output, or gross domestic product, is expected to increase 6% this year — faster than the United States or China.

But there’s a hitch: Investment by Indian companies is not keeping pace. The money that companies put into the future of their businesses, for things like new machines and factories, is stagnant. As a fraction of India’s economy, it is shrinking. And while money is flying into India’s stock markets, long-term investment from overseas has been declining.

Green and red lights are flashing at the same time. At some point soon, the government will need to reduce its extraordinary spending, which could weigh on the economy if private sector money doesn’t pick up.