 While the coronavirus crisis has been hard on the mortgage real estate investment trust mREIT sector, some companies operating within it have had a harder time than others. MFA Financial NYSE: MFA was definitely one such company that really struggled to navigate the crisis. Like most mREITs, MFA experienced a wave of margin calls, and since its assets were less liquid than agency mortgage-backed securities, it suffered through bigger mark-to-market losses mark to market is a way to measure the fair value of accounts that can fluctuate over time. 