Photo: Flickr/Emmanuel Huybrechts

Celebrating prematurely on a long-fought legal battle may cause some trouble for one of the nation's largest banks.

It's not quite over
Bank of America (BAC 0.45%) investors finally got a breath of fresh air last week when a New York judge signed off on the bank's $8.5 billion settlement with institutional investors -- most of it, anyway. But investors can't relax entirely, as dissenting investor American International Group (AIG -0.85%) is still on the case and has persuaded the court to review the ruling once more.

Because the presiding judge over the matter was promoted and ruled on the case prior to her exit, the new presiding judge, Justice Saliann Scarpulla, has agreed to AIG's request that she review the ruling in full. Any new decision on the settlement would likely come in April, according to Justice Scarpulla.

Hostages
Already passing the two and a half year mark, the settlement has been a long road for those investors that approved of the settlement. As the biggest voice of dissent, AIG fought for more money with the argument that the trustee, Bank of New York Mellon (BK 0.07%), was biased, resulting in a sweetheart deal for Bank of America.

With the judgement in favor of the settlement stating that Bank of New York Mellon acted in good faith, the megainsurer's complaints are fully dismissed. But based on New York law, the newly appointed presiding judge is able to review the ruling in full since she had to sign off on her predecessor's decision.

Two of the largest investors, money manager BlackRock (NYSE: BLK) and insurer MetLife (NYSE: MET) argue that AIG is holding the entire settlement hostage, while its interest -- 7% -- is much too small to insist on continuing the legal battle.

Ransom?
The same day that AIG entered the fray, objecting to the $8.5 billion payoff, it has filed a separate $10 billion suit against Bank of America regarding mortgage-backed securities. The investors that are speaking out against AIG's newest bid to delay the settlement are not shy about disclosing that the insurer may be using the one case as leverage for the settlement of the second, larger suit.

In fact, back in Dec. 2013, the insurer had said that it would drop its objections to the $8.5 billion settlement if the bank would settle the independent suit, according to sources close to the matter.

Uncertainty
Though the bank has already "won" the suit, in terms of AIG's objections, the added pressure of another review by a new judge just lends more uncertainty to the bank's legal future. Since uncertainty can drive investors away from a good opportunity, the bank knows that it needs to resolve all of its legal matters -- as soon as possible.

AIG also knows that the leverage from the one case could benefit it in the other, so its very unlikely that it will back off the opportunity to continue delays for the $8.5 billion settlement. Though AIG could be highlighted as a villain in this story, its interests are focused on regaining some of the losses that poorly represented MBSs inflicted during its near-collapse.

For investors, the drawn out legal battle is just one more headache to deal with. But if you follow a sound investment thesis, the impact of one court case shouldn't dissuade you from adding Bank of America to your portfolio.