What: Shares of New York Mortgage Trust (NASDAQ:NYMT) plunged 20% on Wednesday.

So what: New York Mortgage Trust's fourth-quarter results, reported Tuesday afternoon, left a lot to be desired. The company reported net income of $0.01 per share in the fourth quarter. It earned $0.62 per share for the full year 2015.

Disappointing earnings were the result of mark-to-market losses on its investment book, in addition to lower than typical leverage for the mortgage REIT. The company's CEO, Steven Mumma, said that "anticipating further spread widening in the fourth quarter of 2015 and first quarter of 2016, we elected, in large part, to forgo putting our excess liquidity to work, maintaining a higher than usual cash position and lower than normal leverage."

Reduced valuations for its commercial mortgage-backed securities, which drove net income in 2013 and 2014, have come back to bite as writedowns lead to lower earnings and book value. Notably, the company's book value per share fell to $6.54 per share, down from $6.82 at the end of the September-ended quarter, and $7.07 per share at the beginning of 2015.

Now what: The market is absolutely punishing the company, letting shares go for a steep 37% discount to book value after the company spent several months in 2015 trading above book value. In response to an analyst, an executive opined that it was unlikely that New York Mortgage Trust would repurchase shares at a small discount to book.

He did, however, call out 60% of book value as a price at which "it would absolutely make sense" to repurchase stock. We'll have to see if New York Mortgage Trust takes the step to repurchase shares at deep discounts to book.