Advanced architectures for business-to-government (B2G) information sharing can benefit both businesses and government. An essential choice in the design of such an architecture is whether information is shared using a thick or a thin information flow. In an architecture with a thick flow, all information is shared via a shared infrastructure, whereas only metadata and pointers referring to the information are shared via the shared infrastructure in a thin flow architecture. These pointers can then be used by parties to access the information directly. Yet, little is known about what their implications for design choices are. Design choices are influenced by the properties of the architecture as well as the situation in which B2G information sharing takes place. In this paper, we identify the properties of architectures with a thin and thick flow. Next, we determine what this implies for the suitability of the architectures in different situations. We will base our analysis on the case of the Shipping Information Pipeline (SIP) for container transport. While both architectures have their pros and cons, we found that architectures with a thin flow are more suitable when non-standardized, and flexible sharing of sensitive information is required. In contrast, we found that architectures with a thick flow are more suitable when in-depth integration is required.