Asked for comment on the Gotham City report, an AAC representative said the company was preparing a statement.
Last week, AAC chairman Koh Boon Hwee vigorously denied Gotham City Research's findings, saying they were inaccurate and misleading.
AAC's stock was suspended on Thursday afternoon after trading as low as 81.25 Hong Kong dollars ($10.44). The Hong Kong Stock Exchange did not give a reason for the suspension.
AAC's stock has fallen 26 per cent since the first report came out on May 11.
Shenzhen-based AAC is a maker of miniaturised acoustic components including speaker boxes, speakers, receivers and microphones. Apple is one of its main clients.
The group was founded in 1993 by current CEO Benjamin Zhengming Pan and his wife Ingrid Chunyuan Wu, a non-executive director, who together own 40.34 percent of the stock, according to AAC's annual report.
AAC last week posted a 72 per cent profit jump to 1.06 billion yuan for the first three months of the year on 66 per cent revenue growth.
($1 = 7.7844 Hong Kong dollars)