By Amanda Lee and Ying Xian Wong

Indonesia's emerging-market status faces a fresh threat of a downgrade as global index provider S&P Dow Jones Indices flags concerns over the country's market transparency.

S&P DJI said late Tuesday that it has placed Indonesia on a watchlist, a move that could potentially see it downgraded to frontier-market status, casting another shadow over a market already reeling from a loss of investor confidence.

The index provider echoed concerns previously raised by some of its peers, pointing specifically to opaque stock ownership structures and market liquidity.

"If circumstances worsen, S&P DJI may consider implement special treatment for Indonesian securities," the index provider said.