Others have correctly stated that the maximum score is 160. However, the meaningfulness of that score on the WAIS-IV, and for virtually all the Wechsler tests, is highly questionable. In the clinical manuals for most of these tests (not available on line, as far as I can determine), it states that the test is normed from 70 to 130, and that any questions that could only be answered by someone with an IQ above 130 were removed. On their website, they acknowledge that the “reliability [is] lower for the intellectually gifted”— and the more gifted, the less reliable.

This does not mean that someone of IQ 120 might get a score of 160. But it does mean that someone who scores 150, or even 145, might actually have a higher IQ than someone who scores 160. As you get farther above 130, the ability of the test to rank people’s IQ diminishes significantly.