Hello Rosie. Its sounds as if the home being on the market over three months is a requirement of the company before they will consider a FHA (I assume that is what HFA is) loan so you may want to clarify whose time threshold it is. The company can set any guidelines as long as they are within the law and it appears this time threshold is well within their right. The reason a seller is reluctant to accept an offer involving the FHA is that seller has to pay certain costs that the buyer normally pays as well as there being a limit on other costs-in other words a sale involving the FHA is less lucrative for the seller. As to a carry back, here's a scenario of what happened in our last market downturns: A buyer with onlyl 10% down wants to buy a property that the seller wants to sell to the buyer. The banks are either requiring 20% before they underwrite a loan or the interest rates the bank is charging are substantially more with just 10% as opposed to 20% down. In these cases, the seller, being motivated to sell and having adequate equity, would agree to "loan" or hold paper worth 10% (or any other percentage of the sale price). This seller loan (or carryback) to the buyer usually comes with a slightly higher interest rate (though not always) and a shorter loan period. As with the bank, the seller can also foreclose if payments are not made. This is win-win and a great way for a buyer, who may not otherwise have the cash, to qualify for a home loan and also an incentive for a seller who is anxious to sell to get his property sold.