(Adds background on China economy and details on results, shares in paragraph 2, share repurchase program in paragraph 7, net income in paragraph 8)

March 6 (Reuters) - Chinese online retailer JD.com reported fourth-quarter revenue above estimates on Wednesday and upsized its share repurchase program, as aggressive price cuts helped revive demand from consumers grappling with an uncertain economy.

The company's U.S.-listed shares rose 9.4% in premarket trading.

China's shaky economic growth, high youth unemployment and lower wages for office workers have led to consumers tightening their purse strings, driving retailers like JD.com to employ heavy discounts to support sales.

The company reported quarterly net revenue of 306.1 billion yuan ($42.52 billion), compared with analysts' average estimate of 300.04 billion yuan, according to LSEG data.

Some analysts believe JD.com's popularity among cost-conscious buyers has grown over the quarter.

Analysts also said the "suspicious practices" that emerged in an internal audit of its Dada Nexus unit are unlikely to have had a sizeable impact on the company's overall revenue, abating investor concerns.

JD.com said it will repurchase up to $3 billion worth of its shares, including American depository shares, over the next 36 months through March 2027.

The company reported net income attributable to shareholders of 3.4 billion yuan, up more than 13% from 3 billion yuan a year earlier.

($1 = 7.1989 Chinese yuan renminbi) (Reporting by Arsheeya Bajwa in Bengaluru; Editing by Varun H K and Devika Syamnath)