Until recently it was possible to regard the US system of housing finance as one of the best – if not the best – in the world. Just as it was intended to, it has supported very high levels of home ownership, notably among the less prosperous. But the semi-public entities chiefly responsible for that success, and the financial technologies they devised and promoted, are deeply implicated in the housing market crash that now threatens the US and world economies. Will that turmoil lead to a scaling back of their role? Most likely no. They are cast as part of the solution. Their already dominant role in housing finance is set to grow still further.