The Downtown Detroit Business Improvement Zone is funded completely through a special assessment paid by owners of assessable property within the BIZ boundaries. Defined in The BIZ Plan, assessable properties are exclusively taxable properties. Tax-exempt, non-commercial properties are not assessable.

Assessable Properties

The following types of properties are assessable under the BIZ Plan:

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Commercial Properties

Properties with businesses conducting for-profit business, such as retail stores, markets, offices, parking, and restaurants and providing other services.

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Renter Occupied Residential Properties

Residential properties where the owner of the property charges residents rent.

Non-Assessable Properties

The following types of properties are not assessable under the BIZ Plan:

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Property owned by public, governmental entities, such as city, county, state and federal offices, parks, plazas and roads.

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Stadium Authorities

The Stadium Authority owns the land for both Comerica Park and Ford Field. Neither are assessable.

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Religious and Charitable Organizations

Churches, Mosque, Synagogues and other properties owned by religious, or other non-profit and charitable organizations, and used for non-commercial purposes.

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Educational Institutions

Public or private organizations providing education, such as primary and secondary schools and universities.

How Are BIZ Properties Assessed?

The BIZ special assessments are calculated by applying a percentage of assessed value plus a percentage of building floor area for each commercial property. These percentages were established with the adoption of The BIZ Plan in 2014. In addition, there is a per parcel cap of $150,000 and increases in assessments are limited to 3% per parcel per year. The City of Detroit treasurer collects the special assessment with summer taxes.


Growth in BIZ Assessment & Assessed Value

BIZ Assessment Changes Since 2014


Value of Assessable Properties


Change in Assessed Value and BIZ Assessement Since 2014-15

How Are BIZ Properties Contributing to Revenue?

Properties are assessed differently depending on their assessed value and floor area. Of the 581properties that contribute to the BIZ, 44% pay $1,000 or less. The graph below shows how many properties fall within various ranges of assessment in 2020.


Why is There a Delay in BIZ Assessment for New or Renovated Buildings?

The BIZ assessments are based on prior year City of Detroit assessment data, as outlined in The BIZ Plan. Special assessments which are levied with the current summer tax bill are based on property assessment values set in March of the previous year. This causes a delay in when the BIZ will collect the full value of new construction. Depending on construction schedules, this delay can be between one and two years after construction completion.

Infographic showing construction in year 1, city tax collected in year two, and BIZ assessment collected in year 3