Numbers

How many shops someone else can run, by county and industry — for anyone who needs a defensible local figure.

Employer firms by county and age (BDS 2023)

These counts are observed. Coarse firm age exists at county level. “11+” plus firms founded before 1977 is the established stock; a California fine-age mix says ~75% of that stock is 16+ years old.

County	Employer firms	Share 11+	11+ plus old	Est. 16+ firms
Santa Clara	36,608	42.4%	17,596	13,200
Alameda	32,199	41.1%	15,526	11,700
San Francisco	25,746	40.9%	12,344	9,300
Contra Costa	19,485	41.3%	9,405	7,100
San Mateo	16,766	43.4%	8,525	6,400
Sonoma	11,530	45.5%	6,094	4,600
Marin	8,001	46.4%	4,263	3,200
Solano	6,011	42.1%	3,133	2,400
Napa	3,761	46.0%	2,077	1,600
9-county	160,107		78,963	~59,000

North Bay firms are older (Marin / Napa / Sonoma are 45–46% 11+). The South and East Bay have the count. Project Equity’s 77,398 boomer-owned figure is 48% of this firm stock — internally consistent with “half of privately held employer firms.”

How the next tables are estimated: firm counts above are observed (Census BDS 2023, CBP 2022). Age and independence filters are applied rates, not observed local microdata: age rates from U.S. BDS 2023 16+ shares (including firms founded before 1977); independence rates are assumptions (construction 95%, other services 90%, food 75%, retail 60%, and so on). Treat county totals as ±30%. “Main Street” = construction, retail, food/accommodation, other services, health, admin/waste, wholesale, manufacturing.

Size: most locations are too small to sell

CBP 2022, all industries, nine counties: 55.3% of establishments have under 5 employees (115,240 of 208,515). That is where “the business is the owner” lives. The 5–49 band holds 81,536 establishments (39.1%); 10–99 holds 50,865 (24.4%).

Shops someone else can run — Main Street, 5–49 employees, 16+, independent

County	Main Street 5–49	After 16+ rate	After independence	+ remaining professional 5–49
Santa Clara	13,360	4,960	3,900	4,440
Alameda	12,136	4,610	3,630	4,050
San Francisco	7,918	2,830	2,200	2,710
Contra Costa	7,098	2,610	2,050	2,260
San Mateo	5,821	2,140	1,680	1,900
Sonoma	4,776	1,820	1,450	1,550
Solano	2,608	970	760	800
Marin	2,370	870	690	780
Napa	1,446	570	450	480
9-county	57,533	21,400	16,800	19,000

Santa Clara + Alameda are 45% of the core stock. Add Contra Costa and you have the East Bay / South Bay majority. A tighter, more financeable band — Main Street 10–99 employees, same filters — is ~36,100 establishments and ~10,300 transferable.

By industry — where the stock actually sits

Industry	5–49 est.	16+ share (US)	Est. transferable	Why it matters
Health	10,897	38%	3,300	License transfer, payer mix, owner-clinician risk
Food / accommodation	13,934	26%	2,740	Youngest sector; the lease is the deal; franchise noise
Other services	6,042	48%	2,590	Oldest Main Street sector; tacit knowledge is the asset
Construction	6,462	36%	2,220	License, bonded jobs, crew, trucks, pipeline
Retail	9,523	37%	2,140	Inventory + lease; more chains to strip out
Manufacturing	3,363	54%	1,540	Oldest industrial; equipment + customers
Wholesale	3,570	50%	1,420	Customer concentration, supplier terms
Admin / waste	3,742	33%	860	Mix of janitorial routes and real firms
Professional (secondary)	9,405	33%	~2,200	Book of business; non-solicit; who owns the clients

Food looks biggest before filters and is not. It has the most 5–49 locations but the youngest firms (only 26% are 16+) and the most franchise contamination. Other services is the opposite: fewer shops, much older, almost all independent. Construction is the cleanest vertical for a structured file: 95% independent, license-shaped, SBA-familiar, concentrated in Santa Clara / Alameda / Contra Costa / Sonoma.

A local proof point

Santa Clara city (not county), per Project Equity (2021): 1,138 businesses 20+ years old, generating $6.2B — 57% of the city’s small-business revenue — and employing 1 in 3 local workers. Once you leave the campus employers, age is the economic base of that city.

Sources

U.S. Census CBP 2022 (county × NAICS × employment size); U.S. Census BDS 2023 (county firm age; California fine age; U.S. firm age by sector); Project Equity Bay Area report (2023), East Bay note (2023), Santa Clara city fact sheet (2021). Independence rates are stated assumptions. Compiled 2026-08-15.