India's richest man is using nearly all of his company's spare cash to expand Reliance Industries Ltd.'s petrochemical capacity, placing a solid bet the country's growing consumer class will continue to drive growth in the sector -- particularly for plastics -- well into the future.

Reliance, which is controlled by Mukesh Ambani, said it will spend some $12 billion to build new refineries in western India and boost capacity at existing ones. The announcement came as the company posted disappointing quarterly financial results that missed the expectations of Indian stock market analysts.

The Mumbai-based oil and gas giant had $13.9 billion in cash on hand at the end of March, according to financial statements released Friday.

The spending plan brings a lot of clarity on the use of their cash. The strategy of building capacity in chemical and refining to meet Indian demand offsets the fall in gas production, Niraj Mansingka, a Mumbai-based analyst at Edelweiss Capital Ltd., told Bloomberg.

Indian companies focused on providing consumer goods and services within that country have grown at an explosive pace over the past few years, as a rising middle class has provided strong demand for all manner of consumer products. Fully 243 out of 1,000 companies in the IBTimes 1000 list of the world'd fastest-growing publicly-traded companies are headquartered in India, with the vast majority of them in the consumer discretionary and materials industry sub-sector.

Reliance's plan specifically aims to tap into the large demand for plastics in the country.