Complex sentence: In many countries, it is not feasible for banks to borrow at fixed rates for very long terms; in these cases, the only feasible type of mortgage for banks to offer may be adjustable rate mortgages (barring some form of government intervention).
Split into simpler sentences: In many countries, it is not feasible for banks to borrow at fixed rates for very long terms. In these cases, the only feasible type of mortgage for banks to offer may be adjustable rate mortgages (barring some form of government intervention).