Split infinitives are not always wrong, but should be avoided when they result in an awkward construction. Traditional grammar rules and the most formal grammar rules require that we not split infinitives; however, more modern and less formal American English grammar permits split infinitives when they sound better. The GMAT, SAT, and TOEFL tests allow split infinitives as credited (i.e., correct) answer choices.

Source: Split Infinitive - It's not always wrong