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Commercial Real Estate in Northern California: Buy, Lease or Sell

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By Matthew Martinez, Founder, CEO & Managing Broker, Diamond Real Estate Group. California DRE #01869679.

Commercial real estate in Northern California is bought and leased on negotiated terms rather than standard consumer forms, so the letter of intent, the contract or lease, and your own due diligence decide most of the outcome. Price or rent is only one line; who pays operating costs, how long you have to investigate, and what the other side must deliver often matter more.

Diamond Real Estate Group handles commercial sales and leasing for business owners, investors and landlords in Sonoma, Napa, Marin and San Francisco, elsewhere in the Bay Area, and in Lake, Placer, El Dorado, Yolo, Santa Cruz, Sacramento and Monterey counties. Property types include retail and office buildings, industrial and warehouse space, medical office, mixed-use buildings, tasting rooms, winery production space and net-leased investments.

Lease, buy or invest: pick the starting point

The same building can be the right answer for one goal and the wrong one for another. Decide which of these you are doing before you compare properties.

Your goalWhat decides itFirst documents to review
Lease space for your businessTotal occupancy cost, permitted use, build-out and flexibility to grow or leaveLease proposal, operating expense history, zoning for your use
Buy a building to occupyCost of owning versus leasing, zoning, loan terms such as SBA programsTitle report, permits, building condition, loan term sheet
Buy for incomeTenant strength, remaining lease term, net operating income and priceLeases, rent roll, operating statements, estoppels
Sell or recapitalizeLease status, buyer pool and tax planningLeases, expense records, capital work history

How a commercial purchase usually runs

  1. Define the requirement. For an owner-user: size, use, parking, power, loading and timing. For an investor: target return, lease profile and hold period.
  2. Letter of intent. Price, deposit, due diligence period, financing, closing date and the documents the seller will deliver are usually agreed in a nonbinding LOI before attorneys draft the contract.
  3. Purchase and sale agreement. The contract sets the deposit schedule, the seller’s representations, the conditions for cancelling and how prorations are handled.
  4. Due diligence. Leases and rent rolls, operating statements, title and survey, zoning and permits, building systems, accessibility and environmental review. Tenant estoppel certificates confirm lease terms directly with each tenant.
  5. Financing and appraisal. Commercial lenders look at the property’s income and the borrower, and for an owner-user they also look closely at the operating business.
  6. Closing. Rents, deposits and expenses are prorated, leases are assigned to the buyer, and the deed records.

Because commercial buyers rely so heavily on their own investigation and on the representations they negotiate, the length of the due diligence period and the seller’s delivery list deserve as much attention as the price. Our guides to calculating net operating income and testing a marketed cap rate show how to check a seller’s figures, and the estoppel certificate guide covers tenant confirmations.

How a commercial lease is negotiated

A space search starts with your requirements and a budget for total occupancy cost, not base rent alone. Proposals should be compared on rent, annual increases, operating expense pass-throughs, the improvement package, any free rent, the term and renewal options.

Under Civil Code section 1938, every commercial lease form or rental agreement executed on or after January 1, 2017 must say whether the premises have been inspected by a Certified Access Specialist (CASp). That statement does not make a space compliant. It tells you whether an inspection exists, which helps you decide who pays for accessibility work before you sign.

Over a long term, personal guarantees, assignment and subletting rights, and responsibility for the roof, HVAC and structure can cost more than the first year’s rent. Read those clauses as carefully as the rent schedule.

Property tax and other ownership costs

A purchase normally triggers reassessment. According to the State Board of Equalization, the assessor revalues property to its market value as of the date ownership changes, and only the portion that changes hands is reappraised. A buyer’s tax bill can therefore be very different from the seller’s.

In a triple net lease the tenant pays a share of property tax along with insurance and maintenance, so a sale can change what tenants pay. Check each lease’s reimbursement clause before assuming a higher tax bill passes through, and check whether any tenant has a cap on expense increases.

Investors can defer gain by exchanging into or out of commercial property under Section 1031, which covers real property held for business use or investment and exchanged for like-kind real property. Our 1031 exchange guide covers deadlines and California rules.

Commercial guides by task

Each guide below answers a specific question about leasing, buying or selling commercial property in our markets.

Lease space for a business

Buy a building for your business

Invest in commercial property

Specific property types

Local markets

Sell or recapitalize

  • Selling commercial property: pricing, the offering memorandum, tenant estoppels and disclosures, and 1031 or sale-leaseback options for a North Bay sale.
  • Sale-leasebacks: selling the building your business occupies and leasing it back to free up equity.

How Diamond helps commercial clients

For tenants and buyers, Diamond defines the requirement, screens listed properties and owners reached through its own client database and targeted off-market campaigns, compares proposals on total cost, and coordinates the attorneys, lenders, inspectors and consultants a deal needs. For owners, Diamond prices on income, assembles lease and expense records before marketing, and reaches likely buyers through the MLS, its own client database and targeted off-market campaigns. Diamond does not promise access to other brokerages’ office-exclusive listings, and MLS rules govern how a listed property is shared.

Diamond also handles winery production facilities and other wine-industry property, and investors comparing commercial with residential income property can start with our investor guides. Diamond may refer you to partners we work with; you’re free to choose any provider.

This is general information, not legal or tax advice; talk to a California real estate attorney about your lease or purchase contract and a tax adviser about how to hold the property.

Our Commercial Real Estate Team

Commercial assignments at Diamond are led by Matthew Martinez and Kyle Nelson, who work together on sales, leasing and investment across Northern California and the North Bay.

Matthew Martinez, Founder and Broker of Diamond Real Estate Group

Matthew Martinez

Founder & Broker

Matthew Martinez is the Founder and Broker of Diamond Real Estate Group, where he leads complex commercial real estate transactions across Northern California with a focus on strategy, execution, and long-term value creation.

Matthew brings hands-on experience across all major facets of commercial real estate, representing owners, investors, tenants, lenders, and institutions in transactions ranging from small local assets to large, multi-layered commercial portfolios. His background spans office, retail, industrial, mixed-use, land, development sites, and specialized assets, as well as income-producing properties requiring detailed underwriting and operational insight.

What differentiates Matthew is his ability to operate at both the transactional and advisory levels. He is deeply involved in valuation, market analysis, lease structuring, tenant improvements, rent abatement strategies, asset repositioning, and exit planning. He routinely works with investors, family offices, attorneys, asset managers, and lenders, navigating everything from stabilized assets to distressed properties, workouts, and foreclosure-related opportunities.

Matthew has extensive experience representing:

  • Property owners seeking to maximize value through strategic pricing, repositioning, or discreet off-market sales
  • Investors underwriting acquisitions with a focus on cash flow, risk mitigation, and long-term upside
  • Tenants and operators negotiating favorable lease terms, concessions, and build-out structures
  • Sellers of complex or sensitive assets, where confidentiality, timing, and execution are critical

His commercial practice is supported by a data-driven approach, proprietary AI-assisted marketing and analysis tools, and a powerful off-market network that allows him to uncover opportunities not visible to the broader market. This combination enables Matthew to structure deals creatively, solve problems before they become obstacles, and keep transactions moving forward, even in challenging market conditions.

Matthew is known for his clear communication, disciplined process, and results-oriented mindset. He approaches every assignment with the same objective: protect his client's downside, maximize their upside, and deliver a smooth, well-executed transaction from start to finish.

Whether advising on a single commercial property or guiding a long-term investment strategy, Matthew serves as a trusted partner for clients who value experience, precision, and execution in commercial real estate.

Contact Matthew

Kyle Nelson, Diamond Real Estate Group

Kyle Nelson

Commercial & Luxury Residential

At Diamond Real Estate Group, excellence isn't a goal; it's the standard. Kyle Nelson brings a powerful blend of commercial expertise, luxury residential service, and strategic negotiation to every transaction.

With a combined 9 years of real estate experience and millions of dollars in closed and leased volume, Kyle helps the team deliver results with a level of professionalism that stands out across the North Bay.

Growing up in Sonoma County and attending Casa Grande High School and College of Marin helps him bring a unique perspective and insight to the surrounding areas.

Proudly serving Sonoma, Marin, Solano, and surrounding counties, specializing in:

  • Commercial sales, leasing, and investments
  • Industrial and multifamily sales
  • Luxury residential buying and selling
  • Comprehensive advisory and market strategy
His philosophy is straightforwardBuild strong relationships, communicate at the highest level, and negotiate with precision and power.

The result is a service experience that is bold, polished, and consistently elevated, embodying the hallmark of Diamond Real Estate Group. For clients seeking refined service, deep market knowledge, and elite execution, reach out to Kyle for any of your real estate needs.

Contact Kyle

Questions people ask

What costs does a commercial tenant pay beyond base rent?

It depends on the lease type. In a triple net lease the tenant pays base rent plus its share of property tax, insurance and maintenance. In a gross lease the landlord pays those costs out of the rent, and a modified gross lease splits them. Compare total occupancy cost, not base rent.

How long is due diligence on a commercial purchase?

There is no standard period. It is negotiated in the letter of intent and the contract, and it should reflect how many leases, reports and inspections the property needs, including any environmental or survey work.

Do I need a CASp inspection before I lease commercial space?

The lease must state whether the premises have undergone a CASp inspection under Civil Code section 1938. Whether to order one, and who pays for corrective work, is something to negotiate before you sign.

Can I use an SBA loan to buy a building for my business?

SBA 504 and 7(a) loans are both used by businesses buying the property they will occupy, and each has occupancy and structure requirements. Our SBA comparison and owner-user guide explain the differences.

Will buying a commercial property raise its property tax?

Usually, if its market value exceeds the seller’s assessed value. The assessor reassesses to market value as of the date ownership changes, and in net leases that change can flow through to tenants depending on the lease.

Does Diamond handle commercial leasing as well as sales?

Yes. Diamond represents landlords and tenants in leases and buyers and sellers in sales of commercial property.

To discuss a space requirement, a purchase or a sale, send Diamond a short commercial brief with the area, property type, size, budget, intended use and timing.

Sources & notes

Last reviewed October 2026 by Matthew Martinez.

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Matthew Martinez

Diamond Real Estate Group helps clients buy, sell and evaluate homes, vineyards, investment and commercial property across Northern California.

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