There is now an option (under the menu File - System Setup) that allows funds to be kept back if they've been receipted within 3 days (or however many days as specified by you). So for instance, if you receipt money in today but want to make sure it doesn't bounce before you pay it out, you can hold it for a few days. Warning: make sure your Owners are aware of this.
Uncleared Funds for Tenancies not yet started
Sometimes you may receipt in Rent, Bond and Letting Fee at least 2 weeks before the tenant moves in (for students, it can be up to 6 months in advance). You now have a choice to hold back that money from the Owner until the Tenancy actually starts. Do this under File - System Setup and then click on the Company Management Options button. Check the box under the Tenancy heading.