SINGAPORE (BLOOMBERG) - Stats ChipPac Pte, Southeast Asia's biggest semiconductor assembler, said the slide in its bond prices after this month's rating downgrade reflects "market neglect" as the company enjoys the backing of powerful shareholders from China.

The company's 2020 notes fell 1.7 cents to 100.03 cents on the dollar in the five days through May 6 to yield 8.49 per cent, the biggest weekly drop in three months, before rebounding to 100.68 on Tuesday (May 10).

Moody's Investors Service cut its rating by one step on May 5, citing liquidity pressure. Failure to get a US$200 million infusion from its parent Jiangsu Changjiang Electronics Technology Co, or JCET, later this month to fund capacity expansion would trigger another downgrade, it said.

"We expect that cash infusion to come through," Chief financial officer Woo Kwek Kiong said in a phone interview on Tuesday. "Investors don't realize the shareholders behind us. We used to have Temasek, today we have a fund with the Ministry of Finance and China Development Bank as backers. It's being neglected by the market."

Stats ChipPac sold US$425 million of the 2020 notes at par to yield 8.5 per cent in November, a month after Temasek Holdings sold its 83.8 per cent stake in the chipmaker to JCET. The Singapore-based chipmaker last sold five-year bonds at 4.5 per cent in 2013 with higher credit rating under Temasek ownership.

The Singapore-based chip packaging and testing company posted a US$27 million operating loss in the quarter to March 31 while revenues shrank 28 per cent from the final three months of 2015 amid sluggishdemand for smartphones, according to Moody's.