This is a message to whoever wrote this for Yahoo! Finance: You used the wrong pronoun.
Although it looks like you’re dealing with the object of the preposition to, you’re not. The entire clause starting with whomever lasts… is the object of the preposition. The writer should have used whoever, which is the subject of the verb lasts.
Here’s a good rule from grammarbook.com:
The presence of whoever or whomever indicates a dependent clause. Use whoever or whomever to agree with the verb in that dependent clause, regardless of the rest of the sentence.