MUMBAI: Provident and pension fund trusts, which have collectively invested 'thousands of crores' in bonds of the IL&FS group, have filed intervening petitions in the National Company Law Appellate Tribunal over fears that they could lose their money as the bonds come under unsecured debt.The exact amount at stake is not known since many of these are traded instruments. However, investment bankers estimate it to be in thousands of crores since the infrastructure company's bonds - which were 'triple A' rated - were preferred by retirement funds that have a low-risk appetite but still have to get assured returns even when interest rates are low.According to sources, exempted trusts managing funds of employees of public sector companies such as MMTC, IndianOil, CIDCO, HUDCO, IDBI, SBI, and electricity boards of Gujarat and Himachal Pradesh are among those that have filed petitions. There are also PFs of private sector companies like Hindustan Unilever and Asian Paints.In their applications, the funds are calling into question the resolution process itself, including Section 53 of the IBC which spells out the order of priority for distribution of proceeds of the process.The number of PFs filing petitions is likely to rise since they have till March 12 to make their application. So far, over 50 funds, managing retirement benefits of over 14 lakh employees, are understood to have exposure to IL&FS. When contacted, IL&FS spokesperson Sharad Goel said the company would not comment on the issue.The immediate cause of worry for investors is IL&FS filing its group companies into a three-tier classification of Green, Amber and Red.The company has said that of the 302 entities in the group, 169 are Indian companies. Of these, only 22 have been identified to be in a position to meet all their obligations (Green). Another 10 companies can repay their secured creditors (Amber) while 38 companies are distressed and cannot meet their obligations (Red). The company said that 100 entities are still being assessed. If payment is limited to secured creditors, only banks will receive their dues while unsecured bondholders will be left high and dry.IL&FS has been a favourite among PFs because the company was seen to be backed by the public sector, as it was promoted by giants like State Bank of India and Life Insurance Corporation of India.Also, the company structured bonds to suit the requirements of PFs. Some feel that with the resolution taking place close to the Lok Sabha election , default to the PFs could assume a political colour.