S&P warns BHP rating vulnerable to weak iron ore, oil prices

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MELBOURNE, May 4 (Reuters) - Standard & Poor's warned on Monday it may cut BHP Billiton (NYSE: BBL - news) 's credit rating in the next 12 months, reflecting the global miner's commitment never to cut its dividend, even in the face of weak prices for its two biggest earners.

"The negative outlook reflects the increased likelihood that BHP Billiton's financial metrics will worsen in 2016 as a result of lower iron ore and oil prices," S&P said.

"BHP Billiton's commitment to a progressive dividend policy reduces the company's financial flexibility in times of deteriorating market conditions."

However S&P affirmed BHP's long-term corporate credit rating at 'A+' and its short-term rating at 'A-1', the highest among the world's top miners, and said it expected the company to cut costs and capital spending further to shore up its cash flow.

BHP's planned spin-off of its smaller assets into a separate company, South32, would not affect its rating, the agency said.

S&P also affirmed world no.2 iron ore miner Rio Tinto (Xetra: 855018 - news) 's long-term rating at "A-" and short-term rating at "A-2".

It said the company's relatively low capital spending and "excellent position" on the iron ore cost curve globally should help it to meet the cash flow requirements to retain its credit rating.

Last week S&P downgraded top iron ore miner Vale's ratings to "BBB", just two notches above junk level, which Vale called premature at a time it was stepping up output and cutting costs.

(Reporting by Sonali Paul; Editing by Anand Basu and Eric Meijer)