It also affirmed 'B+' long-term issue rating on the company's guaranteed senior notes.
"The outlook is stable," S&P said in a statement.
"We affirmed the ratings because we expect IBREL's financial performance to improve over the next 12-18 months," said Standard & Poor's credit analyst Kah Ling Chan.
"However, the company is likely to remain exposed to execution risk from its rapid expansion."
S&P said that IBREL's property sales picked up to Rs 8 billion between April and June 2015.
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Mumbai-based realty firm continues to face execution risk from its rapid expansion and is also exposed to some project concentration over the next 12-24 months, S&P said.
Three of the company's 10 ongoing projects would account for more than 80 per cent of total revenue from property development.
"We expect IBREL's cash flows to be somewhat volatile through an industry cycle. The timing of the company's project launches can impact cash collections and influence the operating performance and cash flow adequacy," it said.
"The stable outlook reflects our expectation that IBREL will satisfactorily execute its projects and contract sales over the next 12-15 months without any deterioration in its liquidity," said Chan.