GlaxoSmithKline Plc (GSK) has decided to spend roughly $1 billion to raise its stake in its Indian pharmaceutical unit, betting on rising demand in emerging markets as sales in developed economies slow due to a wave of patent expirations.

GSK said Monday it plans to raise its stake in its Indian pharmaceutical unit, GlaxoSmithKline Pharmaceutical, up to as much as 75 percent from 50.7 percent through an open offer in a deal worth about 629 million pounds ($1.02 billion).

With the latest India deal, GSK is set to spend close to $2 billion in roughly a year to increase its holdings in two listed Indian companies, its biggest incremental investment in any country in that period.

Emerging markets such as India and Brazil are an important plank of GSK CEO Andrew Witty’s growth strategy, as he grapples with slower uptake of the company’s products in the developed world.

In February, GSK lifted its stake in its publicly listed Indian consumer healthcare subsidiary, GlaxoSmithKline Consumer Healthcare Ltd, to 72.5 percent from 43.2 percent for $901 million.

“What they are trying to indicate [is] that this market can reward them nicely in the future,” said Sarabjit Kour Nangra, a sector analyst at Angel Broking. “India is a growing market and GSK cannot afford to lose its hold.”

Western drug makers like GSK, Pfizer Inc, and AstraZeneca PLC, covet a bigger share of India’s fast-growing $13 billion drugs market, but have been frustrated by a series of decisions on intellectual property and pricing.

India in August revoked a patent granted to GSK for its breast cancer drug Tykerb, a decision that followed a landmark court ruling disallowing patents for incremental innovations that was a blow to global pharmaceutical firms.

Despite the challenges, Western drug makers have been looking to raise their exposure in Asia’s third-largest economy betting on an increase in healthcare spending.

India currently spends about 5 percent of its GDP on healthcare.

The deal adds to the growing list of multinational companies raising their holdings in the local units as they look to reduce their reliance on traditional markets even as the Indian economy grew at its slowest pace in a decade in the last fiscal year.

Anglo-Dutch consumer goods company Unilever in July completed a deal to raise its stake in the Indian unit Hindustan Unilever to 67.28 percent from 52.48 percent in a deal worth about $3 billion.

GSK will buy up to 20.6 million shares of GlaxoSmithKline Pharmaceutical at 3,100 rupees ($49.85) a share, a premium of 26 percent over its closing market price on Friday. The stock rose as much as 20 percent on Monday to 2,952.15 rupees.

Nangra of Angel Broking said that the premium was attractive for investors who were planning to exit the stock in the near term, but long-term investors were likely to remain invested on future growth potential of the company.

GSK said that it planned to keep the Indian unit listed even after raising its stake.