The Public Accounts Committee says new legislation is needed after Nama "mismanagement" and lack of communication caused a loss of €10m to the taxpayer.
The report followed concerns flagged by the comptroller and auditor general (C&AG) of sales by Nama in 2012 to Luxembourg-based company Clairvue.
Project Nantes, a loan bundle managed by Nama, had a value of €306m in 2006, was acquired by Nama in 2009 for €46.2m and sold for €38.6m in 2012.
The Project Nantes loans were sold through an exclusivity deal to Clairvue-Nantes Luxco SARL (Clairvue) and Nama did not engage with other potential buyers.
During the committee's work, it found there were several mismanagements of loans and caused a loss of €10m.
The report states: "The committee is of the opinion that Nama’s miscalculation, and the decision not to seek up-to-date appraisals of the Project Nantes loan portfolio, directly resulted in a loss of approximately €10m to the taxpayer.
"Nama did not seek independent valuations of the loans associated with Project Nantes in 2012 before it entered negotiations with Clairvue and this led to an undervaluation of the loans of approximately €29m."
The committee agreed with the C&AG’s conclusion that: “Without a contemporaneous asset valuation and a competitive sales process, there is no basis to conclude that Nama achieved the best possible financial outturn from the Project Nantes loan sale”.
The Project Nantes loans were part of a larger loan portfolio being managed on behalf of Nama by asset management company Avestus. Following the sale of Project Nantes, it was discovered that one of the directors of Clairvue had previously been a director of Avestus. This was not disclosed to Nama before the sale was complete.
The committee is "of the opinion that Nama should have done more to investigate the connections between companies managing assets on its behalf, and the companies seeking to purchase Nama loan portfolios."
Green Party TD Neasa Hourigan said the optics of such a deal did not look good.
"It seems clear what happened was not illegal but there was concerning overlap with those involved in the companies and was an overlap known to Nama after the sale, raising huge issues about due diligence that an arm of the state would do when it comes to financial transactions and what kind of recourse we put in place when we set up those bodies.
"To the public, this portrays a closed circle, that assets changed hands but stayed in the same group and that is problematic when a state body is involved."
Fianna Fáil's Marc MacSharry said the committee could not have absolute confidence that a similar "light-handed approach to scrutiny" wasn't replicated on other Nama projects.
The committee says "gaps in the law" have led to the issues at hand but there is little that can be done retrospectively.