A regulatory change that made it harder for lenders to charge prepayment penalties on some adjustable-rate mortgages appears to have done little to dampen the momentum of the net interest margin securitization market. According to an Inside B&C Lending analysis, issuance of NIMs – or securities backed by leftover cash flows, such as early payment charges, from larger deals – increased by 94.9 percent last year, to $16.32 billion. Meanwhile, the typical NIM was…