Logos in Google Maps are visible only via high-spend Google Ads Local Campaigns, not available for chains.
If you were wondering how to make your locations stand out while viewing Google Maps and thought the inclusion of a logo would provide extra visibility, Google unfortunately does not offer this service unless you are paying a considerable amount daily on Google Ads Local Campaigns. Google describes this service as a way to "... to help businesses provide their potential customers the information that they need to decide when and how to visit their stores".
These Local Campaigns are placed all over Google and appear depending on the search queries you are entering. When customers search for businesses or explore a local area within Google Maps, Google can match their searches to your location. Anyone who is located nearby or shows interest in your location may see the ad.
As of writing, chains are not allowed to have logos represented in Google maps. The only time a location can have their logo presented in Google Maps is when the location is part of an account that is not connected to the "chain". And the logo is only presented in non-chains in their knowledge panel, but not while searching via Google Maps. Google has given us details via their API that helps use identify which locations are marked as being part of a chain.
Here you can clearly see the logo attached to the Knowledge Panel. It is not cycled as one of the photos uploaded. Going into Google maps, this logo is not found.
Taking a look at popular chains like Starbucks, you can see that their iconic logo is nowhere to be found in Google's Knowledge Panel or in Maps.
With Google, there always seems to be exceptions to these rules. We are monitoring how they are utilizing logos in search and in Google Maps and will update this article with any relevant findings.