Whenever the cost of a battle far outweighs the benefits of winning, the result is often called a "Pyrrhic victory." A Pyrrhic victory is essentially no victory at all, since the "victor" usually suffers irreparable damage and significant losses of its own. The term Pyrrhic victory comes from the actions of a king named Pyrrhus, who led his Epirian army to a bloody and costly victory over the Roman army around 280 BC. Pyrrhus' losses were so devastating that he is said to have exclaimed his kingdom could not survive another "victory" against the Romans.
A Pyrrhic victory is often ascribed to military campaigns with dubious outcomes for the victors, such as the initial invasion of Normandy during the waning days of World War II. Although the invading Allied troops benefited greatly from some diversionary tactics, the beaches at Normandy were still heavily defended by anti-landing devices, barbed wire and fortified pillboxes with trained machine gunners. The first wave of Allied troops suffered tremendous losses in a futile attempt to breach those defenses. The Allied forces eventually won the battle, but the first few hours were arguably a Pyrrhic victory.
The term Pyrrhic victory has since moved from the military world into the business, legal and social worlds. In business, a company could leverage so much of its assets to acquire another company that the resulting merger sinks it financially. While the company can still claim ownership of a high-profile new division, the resultant costs in terms of employee attrition or available capital could make it a Pyrrhic victory. History is filled with examples of companies which have been crippled or damaged by investing too much money to acquire too little benefit, or those who have pursued expensive legal battles with little hope of a financial recovery through a favorable judgment.
The legal system is also fraught with examples of Pyrrhic victories. Individuals and small companies who take on major corporations in court often find themselves with massive legal bills and no relief in sight. Even if the court finds in their favor and orders the defendants to pay actual or punitive damages, the case could still remain in the appeals process for years. Collection of judgments may also be problematic, and the plaintiff's attorneys are entitled to a significant percentage of those judgments. A victory in court may be emotionally satisfying for the plaintiff, but financially it could be considered a Pyhrric victory.