Collateralized debt obligations (CDOs) su ne samfuran kuɗi da aka tsara kuma ba su ƙarƙashin doka ba, waɗanda ke da kadara a bayansu. An gina CDOs daga wani tarin kadarori masu samun riba mai ƙayyadaddun adadi. Ana raba waɗannan kadarori zuwa sassa daban-daban bisa ga darajar da mai bayarwa ya sanya musu: sassan manya (masu ƙimar AAA), sassan tsakiya (daga AA zuwa BB), da sassan daidaito (waɗanda ba a ba su ƙima ba). Ana amfani da asara a tsari na baya-bayan nan ta fuskar matsayi, don haka sassan ƙanana suna ba da riba mafi girma (ƙimar ruwa) don biya diyya saboda ƙarin haɗarin rashin biya. CDOs sun shahara sosai saboda rikicin jinginar gidaje na sub prime wanda ya taso daga Amurka tun tsakiyar 2007. Wasu suna zargin cewa matsalolin kuɗi na rikicin kuɗi na 2007-2008 sun samo asali ne daga sarkakiyar samfuran CDO, da kuma gazawar samfuran haɗari da murmurewa da hukumomin ba da ƙima ke amfani da su wajen tantance darajar waɗannan samfura daidai. Wasu cibiyoyin da ke sayen CDOs ba su da ƙwarewar sa ido kan aikin bashi da/ko kimanta kuɗin shiga da ake sa ran samu. A gefe guda kuma, wasu masana ilimi suna ganin cewa saboda ba a farashin waɗannan samfura a kasuwa mai buɗewa ba, haɗarin da ke tattare da waɗannan takardu ba a haɗa shi cikin kuɗinsu ba, kuma ba ya nuna girman haɗarin ga masu siye.

Collateralized debt obligations (CDOs) are an unregulated asset-backed and structured credit product. CDOs are constructed from a portfolio of fixed-income assets. These assets are divided into different tranches according to the value placed on the assets by the issuer: senior tranches (rated AAA), mezzanine tranches (AA to BB), and equity tranches (unrated). Losses are applied in reverse order of seniority and so junior tranches offer higher coupons (interest rates) to compensate for the added default risk. CDOs have risen to infamy on the back of the sub prime mortgage melt down led from the US since mid 2007. Some blame the financial woes of the 2007-2008 credit crunch on the complexity of CDO products, and the failure of risk and recovery models used by credit rating agencies to accurately value these products. Some institutions buying CDOs lacked the competency to monitor credit performance and/or estimate expected cash flows. On the other hand, some academics maintain that because the products are not priced by an open market, the risk associated with the securities is not priced into its cost and is not indicative of the extent of the risk to potential purchasers31.

Ta fuskar mark-to-market, inda ake rubuta hannayen jari a takardun asusun kuɗi a farashinsu na yanzu a kasuwa, tare da shanyewar kasuwannin bashi da durkushewar sauƙin cinikin waɗannan kayayyaki (CDO), ya haifar da manyan raguwar darajar kadarori a 2007. Haka kuma, an rasa amincewa sosai game da ingancin tsarin da hukumomin ƙimar bashi ke amfani da shi wajen ba da makin bashi ga rabe-raben CDO, kuma wannan rashin amincewa ya ci gaba har zuwa 2008. Kamfanin bincike na Celent ya kiyasta cewa girman kasuwar CDO ta duniya ya kai kusan dala tiriliyan 2 ya zuwa ƙarshen 2006. CDO sun bambanta a tsari da kadarorin da suke ƙunshe da su, amma ƙa'idar asali iri ɗaya ce. A taƙaice, CDO wata takarda ce ta kuɗi da aka gina don riƙe kadarori a matsayin jingina, da kuma sayar da fakitin kuɗin shiga da aka samu daga waɗannan kadarorin ga masu saka jari. Hanya ce ta mayar da basussuka zuwa takardun kasuwa da za a iya sayarwa (securitisation). Yayin da buƙatar CDO da sauran hannayen jari masu riba mai yawa ke ƙaruwa, bankuna suka ga dama wajen haɗa jinginar gidaje masu haɗari (sub prime) tare da jinginar gidaje masu inganci da sauran basussuka a cikin abu guda. Mai saka jari a CDO yana ɗaukar matsayi a cikin wata hukuma da ke da haɗarin da aka ayyana da riba da aka ayyana, ba kai tsaye a cikin kadarorin da ke ƙasa ba (misali, jinginar gida). Saboda haka, saka jari ya dogara ne da ingancin ma'auni da zato da ake amfani da su wajen ayyana haɗari da riba na rabe-raben. An tabbatar da cewa CDO da yawa an ƙididdige darajarsu fiye da kima, la'akari da rashin ingancin jinginar gidajen da ke cikin yawancinsu, da kuma kumfar farashin gidaje a Amurka da faɗuwar farashinsu daga baya.

As CDO products should be valued on a mark to market basis (where securities are marked in balance sheets at current market price), this coupled with the paralysis in the credit markets and the collapse of liquidity in these products led to substantial write-downs in 2007. Additionally a major loss of confidence has occurred in the validity of the process used by ratings agencies to assign credit ratings to CDO tranches and this loss of confidence has persisted through 2008. Research firm Celent estimated the size of the CDO global market at close to $2 trillion by the end of 2006. CDOs vary in structure and their underlying assets, but the basic principle is the same. Essentially a CDO is a security constructed to hold assets as collateral and to sell packages of cash flows from those assets to investors. It is a means to securitise debts. With growing demand for CDOs and other high yielding securities investment, banks saw an opportunity to package up sub prime mortgages together with higher grade mortgages and other debts into one vehicle. A CDO investor takes a position in an entity that has a defined risk and reward, not directly in the underlying assets (eg the mortgage). Therefore, the investment is dependent on the quality of the metrics and assumptions used for defining the risk and reward of the tranches. Many CDOs have been proven to be hopelessly overvalued in light of the poor quality of underlying mortgages included in many of them and in light of the US housing bubble, and subsequent price slide.

CDO ne masu bayarwa, galibi bankunan saka hannun jari, suna samun kwamishin a lokacin fitarwa da kuɗin gudanarwa a tsawon rayuwar CDO. Masu saka hannun jari sau da yawa sun yi amfani da bashi sosai, suna karɓar lamuni don cin moriyar bambancin riba mai kyau tsakanin manyan dawowar sassan CDO da kuɗin da suke biya na karɓar bashin.

CDO issuers, usually the investment banks, earn commissions at time of issue and management fees over the life of the CDO. Investors have often been highly leveraged using loans to benefit from the positive spread between the high returns on tranches of CDOs and their cost of borrowing.

Yakin wasu cibiyoyi sun yi yawan karbar bashi fiye da kima a neman riba mai yawa. Wani misali mai sauƙi ya nuna haka. Banki mai jari na dala miliyan 1 zai karbi bashin dala miliyan 29 don sayen kayan hada-hadar kudi da aka tsara (structured product) kamar CDO, misali wanda aka gina a kan bashin jinginar gidaje, na dala miliyan 30. Ribar da ake biya a kan CDO na dala miliyan 30 za ta fi kudin ruwan bashin dala miliyan 29 yawa. Kashi ashirin cikin dari (dala miliyan 6) na jinginar gidajen za su shiga cikin rashin biyan bashi (default), tare da ƙarancin dawo da kuɗi (recovery rate) kamar kashi biyu bisa uku, ko dala miliyan 4. Wannan zai haifar da asarar jari na dala miliyan 2, wadda ta share gaba ɗaya jarin asali na dala miliyan 1 kuma ta bar asarar net na dala miliyan 1 (jari na minus dala miliyan 1, kadarori na dala miliyan 28 da ke ci gaba da faɗuwa, da bashi na dala miliyan 29). Lokacin da wannan misali ya faru a zahiri, amma a biliyoyin dala, za a iya fahimtar girman matsalar. Tare da hadewar karbar bashi (leveraging) da kuma koma-bayan kasuwar gidaje mai tsanani, asarar da aka yi a kan waɗannan kayayyaki ta kasance mai muni ƙwarai. Har ma manyan ɓangarorin bashi masu inganci sun sha asara mai yawa. Kamfanin Bear Stearns, wanda a lokacin shi ne kamfanin hada-hadar hannun jari na Amurka na biyar mafi girma, amma yanzu ya rushe, ya ce a ranar 18 ga Yuli, 2007 cewa masu saka jari a manyan asusun hedge guda biyu nasa da suka faɗi ba za su samu kusan komai ba, bayan "faɗuwar darajar" da ba a taba gani ba a darajar hannayen jarin da aka yi amfani da su wajen caca a kan jinginar gidajen subprime.

Many institutions became vastly over-leveraged in the seeking of high returns. A simple example demonstrates this. A bank with $1 million of capital would borrow $29 million to then buy $30 million of structured product like a CDO, for example written over mortgage debt. The interest payments on the CDO of $30 million are much higher than the cost of borrowing on the $29 million. Twenty percent ($6 million) of the mortgages go into default, with a poor recovery rate (say 2 thirds or $4 million). This leaves a capital loss of $2 million which wipes out completely the original $1 million of capital and leaves a net loss of $1 million (capital of minus $1 million, assets of $28 million which are falling, and liabilities of $29 million). When the above example becomes real, but is in billions of dollars then the scale of the problem can be felt. With the mix of borrowings (leveraging) and now severe housing market downturn, the losses have been catastrophic on these products. And even the higher quality tranches of debt have suffered significant losses. The now defunct Bear Stearns, which at the time was the fifth-largest U.S. securities firm, said on July 18, 2007 that investors in its two failed hedge funds will get little if any money back after “unprecedented declines” in the value of securities used to bet on subprime mortgages.