The scrap metal-dealer-turned-billionaire has made multiple stock purchases in January and February, raising his stake in the company to 68.46 per cent as of Feb. 20 from 66.93 percent at the start of the year.
The latest regulatory filing, published on Wednesday, showed that Agarwal purchased 210,000 shares at 851.48 pence per share on Feb. 20 through his investment vehicle, Volcan Investments Ltd.
Vedanta's stock closed at 842 pence on Wednesday on the London Stock Exchange.
The company, grappling with regulatory hurdles and low commodity prices, was one of three miners to be demoted from the FTSE-100 index last year. Its stock has lost nearly a third of its value in the last 12 months.
Liberum analyst Ben Davis said that the latest purchases by Agarwal might be an attempt to signal to investors that Vedanta's stock has been oversold.
While promoters buying shares in their companies to shore up their stock price is nothing new, the frequency of Agarwal's purchases has prompted trader chatter that he may be looking to make an offer to take the firm private.
Neither Vedanta nor Volcan Investments were available for comment when contacted by Reuters.
Taking the company private would severely restrict Vedanta's access to public funds. It would also clash with Agarwal's ambition of growing the company to compete with the likes of Rio Tinto and BHP Billiton .
UK listing requirements mandate that at least 25 percent of a company's stock be available for trading.
The next biggest shareholders in Vedanta are Standard Life Investments Ltd, with a 7.85 percent stake, and BlackRock Investment Management (UK) Ltd with a stake of over 4 percent.
GIC Private Ltd, Capital World Investors and Credit Suisse Asset Management each have a stake of more than 2 percent in the company, according to Thomson Reuters data.
Independent directors at Essar Energy, the other Indian resources company in the FTSE-250 index, this week shot down a bid from its largest shareholder and founders, India's billionaire Ruia brothers, saying the offer undervalued the company.