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The Use of Funds Taxonomy provides a standardized, hierarchical classification system for categorizing how US municipal bond proceeds are used. This three-level hierarchy helps investors understand and analyze US municipal bonds based on their intended purpose.

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Taxonomy Structure

The taxonomy consists of three levels, from broadest to most specific:
  1. Use Sector (Top Level) - 10 broad sectors representing major areas of public infrastructure and services
  2. Use Category (Middle Level) - 31 categories providing more specific functional classifications
  3. Uses of Proceeds (Bottom Level) - 73 specific uses describing the precise purpose of bond proceeds

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How the Hierarchy Works

Each bond’s use of proceeds maps to exactly one category, and each category belongs to exactly one sector. This creates a clear hierarchical relationship: Use Sector → Use Category → Uses of Proceeds For example:
  • Sector: transportation
  • Category: airport
  • Proceeds: airport
Or a more complex example:
  • Sector: education
  • Category: higher education
  • Proceeds: public college, private college, community college, or student housing

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Important Note

A single bond may have multiple sectors or categories if the uses of proceeds are diverse enough. For example, a bond that funds both a hospital and a school would be classified under both the healthcare and education sectors.

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Complete Taxonomy Reference

The table below shows all possible values across the three-level hierarchy. The sector is shown only on the first row of each sector group for readability.
Use SectorUse CategoryUses of Proceeds
developmenteconomic developmentdevelopment district, hospitality, office buildings, public buildings, shopping centres
industrial developmentindustrial development, pollution control
educationhigher educationcommunity college, private college, public college, student housing
pre-schoolpre-school and daycare
primary and secondary educationcharter school, public school district, standalone public school
governmentessential servicescorrectional facilities, courts, fire, police
general purposetribal
healthcarehealth systemhealth system
hospitalscritical access hospital, specialty hospital, standalone hospital
senior livingassisted living, continuing care retirement community, independent living, nursing home
housingmilitary housingmilitary housing
multi-family housinglocal hfa multi-family housing, local standalone multi-family housing, state hfa multi-family housing
public housingpublic housing
single family housinglocal hfa single family housing, local standalone single family housing, state hfa single family housing
miscellaneousmiscellaneousmiscellaneous
recreationculturecommunity centre, library, museum
recreationalparks, stadium
securitizedgas prepaygas prepay
student loanstudent loan
transportationairportairport
bridgesnon-toll bridges, regional toll bridges, state toll bridges
parkingparking facilities
portcombined port authority, standalone port
public transitbuses, ferries, trains
roadsnon-toll roads, regional toll roads, state toll roads
utilitycommunicationbroadband, telephone
electricalelectrical infrastructure
gasgas infrastructure
poweralternative source power, coal power, gas power, nuclear power, solar power, wind power
waste removalwaste removal
water and sewerflood control, irrigation, sewer, storm water, water

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API Fields

The taxonomy is available through three fields in our US municipal bonds API:

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use_sectors

Array of sectors (top level). Returns the broadest classification for a bond’s use of funds. Example values: ["education"], ["transportation"], ["utility"] Available sectors (10 total):
  • development
  • education
  • government
  • healthcare
  • housing
  • miscellaneous
  • recreation
  • securitized
  • transportation
  • utility

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use_categories

Array of categories (middle level). Returns more specific functional classifications. Example values: ["higher education"], ["airport"], ["power"] Available categories (31 total):
  • airport
  • bridges
  • communication
  • culture
  • economic development
  • electrical
  • essential services
  • gas
  • gas prepay
  • general purpose
  • health system
  • higher education
  • hospitals
  • industrial development
  • military housing
  • miscellaneous
  • multi-family housing
  • parking
  • port
  • power
  • pre-school
  • primary and secondary education
  • public housing
  • public transit
  • recreational
  • roads
  • senior living
  • single family housing
  • student loan
  • waste removal
  • water and sewer

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uses_of_proceeds

Array of specific uses (bottom level). Returns the most detailed classification of how bond proceeds are used. Example values: ["public college"], ["airport"], ["solar power"] Available uses (73 total):
  • airport
  • alternative source power
  • assisted living
  • broadband
  • buses
  • charter school
  • coal power
  • combined port authority
  • community centre
  • community college
  • continuing care retirement community
  • correctional facilities
  • courts
  • critical access hospital
  • development district
  • electrical infrastructure
  • ferries
  • fire
  • flood control
  • gas infrastructure
  • gas power
  • gas prepay
  • health system
  • hospitality
  • independent living
  • industrial development
  • irrigation
  • library
  • local hfa multi-family housing
  • local hfa single family housing
  • local standalone multi-family housing
  • local standalone single family housing
  • military housing
  • miscellaneous
  • museum
  • non-toll bridges
  • non-toll roads
  • nuclear power
  • nursing home
  • office buildings
  • parking facilities
  • parks
  • police
  • pollution control
  • pre-school and daycare
  • private college
  • public buildings
  • public college
  • public housing
  • public school district
  • regional toll bridges
  • regional toll roads
  • sewer
  • shopping centres
  • solar power
  • specialty hospital
  • stadium
  • standalone hospital
  • standalone port
  • standalone public school
  • state hfa multi-family housing
  • state hfa single family housing
  • state toll bridges
  • state toll roads
  • storm water
  • student housing
  • student loan
  • telephone
  • trains
  • tribal
  • waste removal
  • water
  • wind power

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Using the Taxonomy

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Understanding Bond Data

When you retrieve bond data from the muni_reference endpoint, you’ll see all three taxonomy levels populated: 
{
  "uses_of_proceeds": ["public college"],
  "use_categories": ["higher education"],
  "use_sectors": ["education"]
}
This tells you that the bond is used for a public college (specific), which is a type of higher education (middle level), within the education sector (broad).