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<p><b>New page</b></p><div>{{Infobox Company<br />
| name = Day & Zimmermann<br />
| image =<br />
| image_caption = Day & Zimmermann operations<br />
| type = Private (family-owned)<br />
| industry = Defense, engineering, staffing<br />
| address = 1500 Spring Garden Street<br />
| neighborhood = Spring Garden<br />
| coordinates = 39.9618,-75.1630<br />
| phone =<br />
| website = https://www.dayzim.com<br />
| established = 1901<br />
| founder = Charles Day, John Zimmermann<br />
| ceo =<br />
| employees = 51,000+<br />
| revenue = $3+ billion<br />
| status = Active<br />
}}<br />
<br />
'''Day & Zimmermann''' is a '''privately held, family-owned''' industrial conglomerate headquartered in [[Philadelphia]]. Founded in '''1901''' by '''Charles Day''' and '''John Zimmermann''', the company has grown into one of America's largest private companies with over '''51,000 employees''' and revenues exceeding '''$3 billion'''. Day & Zimmermann operates in three main sectors: '''defense and munitions''', '''engineering and construction''', and '''staffing services'''. The Yoh family has owned and operated the company since 1961, maintaining Philadelphia headquarters and representing one of the city's most significant privately held enterprises.<ref name="dayzim-official">{{cite web |url=https://www.dayzim.com |title=Day & Zimmermann |publisher=Day & Zimmermann |access-date=December 31, 2025}}</ref><br />
<br />
== History ==<br />
<br />
=== Origins (1901) ===<br />
<br />
Day & Zimmermann was founded in '''1901''':<br />
<br />
'''Beginning:'''<br />
* '''Charles Day''' and '''John Zimmermann''' founded company<br />
* Engineering consulting origin<br />
* Philadelphia base<br />
* Industrial focus<br />
<br />
=== Early Engineering ===<br />
<br />
'''Initial business:'''<br />
* Power plant engineering<br />
* Industrial consulting<br />
* Utility industry work<br />
* Growing reputation<br />
<br />
=== World War I ===<br />
<br />
'''Defense entry:'''<br />
* Munitions production began<br />
* Government contracts<br />
* Expanded capabilities<br />
* Strategic importance<br />
<br />
=== Yoh Family Acquisition (1961) ===<br />
<br />
'''New ownership:'''<br />
* '''Harold Yoh''' acquired company<br />
* Family ownership began<br />
* Professional management<br />
* Diversification strategy<br />
<br />
=== Growth ===<br />
<br />
'''Expansion:'''<br />
* Staffing business added<br />
* Defense growth<br />
* Engineering expansion<br />
* National presence<br />
<br />
== Business Segments ==<br />
<br />
=== Munitions and Defense ===<br />
<br />
'''Government services:'''<br />
* Ammunition production<br />
* Munitions demilitarization<br />
* Weapons systems maintenance<br />
* Government contractor<br />
<br />
=== Engineering and Construction ===<br />
<br />
'''Industrial services:'''<br />
* Power generation<br />
* Nuclear facility support<br />
* Industrial construction<br />
* Maintenance services<br />
<br />
=== Yoh Staffing ===<br />
<br />
'''Workforce solutions:'''<br />
* Technical staffing<br />
* Engineering placement<br />
* IT staffing<br />
* Contract employees<br />
<br />
== Operations ==<br />
<br />
=== Munitions ===<br />
<br />
'''Defense work:'''<br />
* Operates Army ammunition plants<br />
* Munitions production<br />
* Demilitarization<br />
* Critical defense contractor<br />
<br />
=== Power Industry ===<br />
<br />
'''Engineering:'''<br />
* Nuclear power plant services<br />
* Fossil fuel plants<br />
* Maintenance and outages<br />
* Technical support<br />
<br />
=== Staffing ===<br />
<br />
'''Yoh brand:'''<br />
* Technical and engineering staffing<br />
* Contract and direct hire<br />
* National presence<br />
* Fortune 500 clients<br />
<br />
== Philadelphia Headquarters ==<br />
<br />
=== Spring Garden Location ===<br />
<br />
'''Corporate base:'''<br />
* 1500 Spring Garden Street<br />
* Center City Philadelphia<br />
* Long-term presence<br />
* Family commitment to city<br />
<br />
=== Employment ===<br />
<br />
'''Local jobs:'''<br />
* Headquarters staff<br />
* Regional operations<br />
* Professional positions<br />
* Community employer<br />
<br />
=== Yoh Family ===<br />
<br />
'''Family ownership:'''<br />
* Three generations<br />
* Philadelphia connection<br />
* Long-term thinking<br />
* Civic involvement<br />
<br />
== Company Culture ==<br />
<br />
=== Family Ownership ===<br />
<br />
'''Private company:'''<br />
* No public shareholders<br />
* Long-term perspective<br />
* Values-driven<br />
* Employee focus<br />
<br />
=== Safety Focus ===<br />
<br />
'''Core value:'''<br />
* Munitions require safety culture<br />
* Zero harm goal<br />
* Training emphasis<br />
* Recognition programs<br />
<br />
=== Community ===<br />
<br />
'''Engagement:'''<br />
* Philadelphia philanthropy<br />
* STEM education support<br />
* Community partnerships<br />
* Employee volunteering<br />
<br />
== Industry Position ==<br />
<br />
=== Defense Contractor ===<br />
<br />
'''Scale:'''<br />
* Major ammunition producer<br />
* Government contracts<br />
* Critical capabilities<br />
* Long-term relationships<br />
<br />
=== Engineering ===<br />
<br />
'''Specialization:'''<br />
* Nuclear industry expertise<br />
* Power generation<br />
* Industrial maintenance<br />
* Technical services<br />
<br />
=== Staffing ===<br />
<br />
'''Market position:'''<br />
* Technical staffing leader<br />
* National footprint<br />
* Fortune 500 clients<br />
* Growing sector<br />
<br />
== Challenges ==<br />
<br />
=== Government Contracts ===<br />
<br />
'''Dependencies:'''<br />
* Government budget cycles<br />
* Contract competition<br />
* Political factors<br />
* Regulatory requirements<br />
<br />
=== Labor Market ===<br />
<br />
'''Workforce:'''<br />
* Technical talent competition<br />
* Training requirements<br />
* Retention challenges<br />
* Skills gaps<br />
<br />
=== Industry Changes ===<br />
<br />
'''Evolution:'''<br />
* Energy industry transition<br />
* Defense priorities<br />
* Technology changes<br />
* Market dynamics<br />
<br />
== Leadership ==<br />
<br />
=== Yoh Family ===<br />
<br />
'''Ownership:'''<br />
* Three generations since 1961<br />
* Family governance<br />
* Philadelphia commitment<br />
* Long-term vision<br />
<br />
=== Management ===<br />
<br />
'''Professional leaders:'''<br />
* Segment presidents<br />
* Operational expertise<br />
* Industry veterans<br />
* Board oversight<br />
<br />
== Future ==<br />
<br />
=== Strategy ===<br />
<br />
'''Direction:'''<br />
* Core business focus<br />
* Government services<br />
* Technical staffing growth<br />
* Strategic investments<br />
<br />
=== Trends ===<br />
<br />
'''Opportunities:'''<br />
* Defense spending<br />
* Infrastructure investment<br />
* Technical skills demand<br />
* Energy sector services<br />
<br />
== See Also ==<br />
* [[Philadelphia Businesses]]<br />
* [[Spring Garden]]<br />
<br />
== References ==<br />
<references /><br />
<br />
== External Links ==<br />
* [https://www.dayzim.com Day & Zimmermann]<br />
* [https://www.yoh.com Yoh Staffing]<br />
<br />
{{#seo:<br />
|title=Day & Zimmermann - Philadelphia's Family-Owned Defense and Engineering Giant<br />
|description=Day & Zimmermann, the family-owned industrial company headquartered in Philadelphia since 1901. Defense munitions, engineering, and staffing with 51,000 employees and $3+ billion revenue.<br />
|keywords=Day & Zimmermann, Philadelphia company, defense contractor, Yoh family, munitions, engineering, staffing services<br />
|type=Article<br />
}}<br />
<br />
[[Category:Businesses]]<br />
[[Category:Defense Industry]]<br />
[[Category:Private Companies]]<br />
[[Category:Spring Garden]]</div>
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