* Q2 net profit 53.8 bln rupees vs estimate 53.9 bln
* Gross refining margins at $9.5/bbl vs $10.1/bbl year ago
* Shares close 0.5 pct up ahead of results
By Prashant Mehra
MUMBAI, Oct 15 (Reuters) - Indian conglomerate Reliance Industries Ltd posted its fourth consecutive drop in quarterly profit but met market estimates as refining margins rebounded and treasury gains from its huge cash pile bolstered profits.
Reliance, controlled by billionaire Mukesh Ambani, Asia's second-richest man, said its quarterly profit fell to 53.76 billion rupees ($1.01 billion), down 5.7 percent from a year earlier.
The results come with the company facing a slump in investor interest, shrinking profits amid a slowdown in its core energy business and as recent forays into consumer-focused segments, such as telecom and retail, are yet to garner profits.
Reliance said net sales for the September quarter rose 15 percent to 903.35 billion rupees.
A Reuters poll of brokerages had forecast net profit of 53.9 billion rupees for the quarter ended September 30, with net sales expected at 933.4 billion rupees.
The company, which operates the world's biggest refining complex in western India, reported gross refining margins of $9.5 a barrel for the July-September quarter, compared with $10.1 a barrel a year earlier. The company reported refining margins of $7.6 a barrel in the June quarter.
Refining margins have risen over the past quarter helped by higher demand and unplanned refinery shutdowns in Asia. Analysts had expected Reliance to report margins of around $9/barrel.
Other income of 21.12 billion rupees, most of it through treasury gains, accounted for 31 percent of the company's pre-tax profit for the quarter.
Shares in Reliance, valued at $50.3 billion, have risen 18.8 percent so far this year, but still lag the 21 percent rise in the main stock index. Ahead of the results, the stock closed up 0.5 percent.