BENGALURU Blackstone Inc's delisting offer for India's R Systems International Ltd was unsuccessful as the U.S. investment fund failed to draw enough interest from public shareholders, the manager to the offer said on Monday.

Blackstone, which in November said it would buy a near 52% stake in the IT services firm for $359 million, needed to raise its stake to 90% for the delisting proposal to work.

However, the offer secured only share tenders from 11.45% of public shareholders, compared to the minimum 38.33% required to raise Blackstone's stake to 90%, offer manager Kotak Mahindra Capital said in a disclosure.

The proposal had opened on April 21 and closed earlier on Monday.

Blackstone had in March raised its offer price for public shareholders to 262 rupees per share, compared to the 246 rupees it offered when the delisting proposal was first approved.

R Systems' shares closed at 250.70 rupees on Monday, a 4.3% discount to its sweetened delisting offer price.

Shares of the firm, which has a market capitalisation of 29.51 billion rupees, have risen 6.7% since the Blackstone deal was first announced in November.

(Reporting by Nandan Mandayam in Bengaluru; Editing by Shailesh Kuber)