Whatever they want

I just got a call from a verification client who said that a prospect has asked to see monthly returns; he asked if he can provide them a GIPS(R) presentation just with the monthly returns rather than annual?

You can have monthly returns in your presentation but must also have annual. You can give a prospect whatever they ask for, even if it's not in line with the Global Investment Performance Standards (e.g., a representative account or an equal-weighted composite presentation), as long as you also give them the appropriate compliant presentation.