Bank of America ($13.24 0.03%) asked a New York appellate court to overturn a lower court’s decision to accept a lower standard of proof in mortgage-backed securities litigation filed by MBIA, Bloomberg News reported.

Previously, Justice Eileen Bransten ruled that bond insurer MBIA does not need to show ‘a causal link’ between misrepresentations that BofA allegedly made about loans backing MBS deals and claims MBIA paid out on those deals. Without the requirement of a causal link, MBIA has an easier standard of proof.

Since the ruling creates more risk for BofA in court, it prompted the bank to ask for appellate review of the decision this week, Bloomberg said.