In a filing to the Singapore stock exchange Friday, Noble said "we categorically reject the unfounded allegations."
On Thursday, Noble shares fell as much as 9.3 percent in intraday trade to 0.835 Singapore cents—their lowest level since September 2013— before ending down around 5.5 percent. Short interest in the share surged to 60.7 million shares Thursday from just 9.9 million on Wednesday. On Friday, the stock recovered sharply, climbing 4.1 percent in late trade.
To be sure, many traders may be taking quick profit on short sales or they may be unwilling to hold the position over the weekend. But a trader at a local securities firm didn't cite those factors.
"Most feel that there is nothing significantly new in their report," he said via email.
Read MoreNoble Group is knee deep in muddy waters
The latest critical report followed a series of three reports starting in February from Iceberg Research, with the first headlined "Noble Group, a repeat of Enron." Noble also denied many claims in those reports and said they were written by a disgruntled former employee.
Even analysts critical of Noble have praised the company's handling of the matter.
"Noble has been utterly professional throughout the whole thing," Robert Medd, a partner at private research house, GMT Research, told CNBC Friday.
Medd is also critical of Noble's accounting practices, calling the booking of future profits "quite aggressive" and "presumptuous," and noting that the companies payables have "ballooned," but he added that it's not necessarily fraudulent. Medd is also critical of Noble's level of disclosure.
But of Muddy Waters' report he says: "It makes for a great title," adding it was written in an "entertaining" way.
Some of the fire in the Muddy Waters report may have gotten dampened by the final four pages of the 14-page report, which referenced an analysis of Noble's fourth-quarter conference call by QVerity, a U.S.-based firm formed by former Central Intelligence Agency employees and which provides behavioral analysis for "deception detection."
QVerity determined it was "highly likely" some of Iceberg's allegations must be true based on how CEO Yusuf Alireza answered questions from analysts.
"Alireza begins his response with overly polite behavior, thanking the analyst and using his name. This is a form of manipulation behavior," QVerity was quoted as saying in the Muddy Waters' report.
"The market doesn't really know what to make of it," OCBC's Wong said, noting that Alireza usually answers conference call questions in that manner.
For its part, QVerity said in response to e-mailed questions that it only considers "overly polite behavior" deceptive if that isn't the way that person would typically respond and if there is a cluster of two or more deceptive behaviors in response to a single question. QVerity said it tends to find an intent to deceive "more often than not," but noted that the firm's services are sought when the subject has a reason to withhold information or engage in deceptive behavior.
Wong is sticking with a Hold call on the stock, with a recommendation to buy if it falls below 85 Singapore cents or lower.
"I don't think the Noble-Muddy Water thing has blown over yet," Wong said, adding he's still examining Noble's rebuttals. "The market is uncertain, but definitely nobody is denying that more information and more disclosure are always better."