The term dry lending relates to preferential lending that does not require assets to be held under the management of the funding provider. You may have assets held with other banking groups, which will be considered when calculating the best loan interest rate available. However, at no point are you required to move these assets to the funding provider.
Dry lending is particularly advantageous because all your assets (wherever they are held) can be considered when looking at affordability ratios and repayment schedules.
Dry loans can be used to ensure you maintain liquidity and don’t have to liquidate assets to free up capital to buy a property or move assets around to other banking groups.