Forbes: 19 Most Profitable Small Businesses

1. Offices of Chiropractors

Average Pretax Margin: 16%

Some question the medicinal value of their service. Hard to question their financial performance, though.

2. Other Accounting Services

Average Pretax Margin: 15.5%

Various accounting, bookkeeping, billing and tax preparation services in any form, handled not necessarily by a Certified Public Accountant .

3. Offices of Dentists

Average Pretax Margin: 15.4%

Dentists enjoy operating scale–that is, they can handle several patients at once. Some of the equipment is expensive, but hygienists don't cost much. Better yet, a lot of customers pay out of pocket. That gives dentists more pricing power relative to other medical providers.

4. Tax Preparation Services

Average Pretax Margin: 15.1%

Who likes doing their taxes? Exactly.

5. Sales Financing

Average Pretax Margin: 15.1%

These companies are popular in a credit crunch. They lend money for the purpose of providing collateralized goods through a contractual installment sales agreement, either directly from, or through, arrangements with dealers.

6. Freestanding Ambulatory Surgical and Emergency Centers

Average Pretax Margin: 14.8%

Services include orthoscopic and cataract surgery on an outpatient basis; setting broken bones, treating lacerations, or tending to patients suffering injuries as a result of accidents, trauma or other problems that need immediate attention. These facilities include operating and recovery rooms, and specialized equipment, such as anesthetic or X-ray machines. In short: If a big rock falls on your leg, you're going to find a way to fix it–fast.

7. Lessors of Mini-Warehouses and Self-Storage Units

Average Pretax Margin: 12.3%

More mailbox money–and little upkeep required. No wonder storage units are so profitable.

8. Offices of Optometrists

Average Pretax Margin: 12.2%

These practitioners have the degree of O.D. (Doctor of Optometry). They examine, diagnose, treat and manage diseases and disorders of the human visual system–that means prescribing and/or providing eyeglasses, contact lenses, low vision aids and vision therapy. These outfits operate private or group practices (clinics and centers) or in the facilities of others, such as hospitals or HMO medical centers.

9. Lessors of Nonresidential Buildings (Except Mini-Warehouses)

Average Pretax Margin: 11.6%

Included in this industry are owner-lessors of nonresidential buildings; renters of real estate who then act as lessors in subleasing it to others; and those who provide full-service office space, be it on a lease or service contract basis. The group also may include those who manage property themselves or have another establishment manage it for them. There's a term that describes the juicy economics at play here: mailbox money.

10. Insurance Agencies and Brokerages

Average Pretax Margin: 11.3%

Included here are insurance agents and those that provide other services, like claims adjustments. Successful agents enjoy annuity-style profit streams: They nab an up-front commission upon selling a policy, as well as fees each year that the policy stays in place.

11. Offices of Physicians (except Mental Health Specialists)

Average Pretax Margin: 11.2%

Eight years of medical school and a tortuous residency pay off. No matter what the economy is doing, there are always sick people to treat. Still, general docs have steadily lost pricing power at the hands of large insurance providers.

12. Consumer Lending

Average Pretax Margin: 11.1%

Comprises companies primarily engaged in making cash loans or extending credit through various means (except credit cards and sales finance agreements). Two words: pricing power.

13. Offices of Physical, Occupational and Speech Therapists, and Audiologists

Average Pretax Margin: 11%

These outfits operate private or group practices (clinics and centers) or in the facilities of others, such as hospitals or HMO medical centers. More proof that specialization pays.

14. Investment Advice

Average Pretax Margin: 11%

These are financial planners who don't have the authority to execute trades. Few things are as opaque as fees for financial-services fees–which is probably why this industry makes our list.

15. Veterinary Services

Average Pretax Margin: 10.5%

Includes licensed practitioners of veterinary medicine, dentistry, surgery and testing. If Spot needs help, even the expensive kind, he's going to get it.

16. Diagnostic Imaging Centers

Average Pretax Margin: 10.5%

Small fry may have difficulty raising the scratch to buy expensive equipment; once it's installed, though, economies of scale start to kick in. Depending on the type of lab, the marginal cost of doing "one more" test–thanks to typically lean staffing–can be very small.

17. Offices of General or Family Practitioners

Average Pretax Margin: 10.4%

Insurance companies do all they can to crimp doctors' payouts, but treating junior's fevers still turns a handsome profit.

18. Support Activities for Oil and Gas Operations

Average Pretax Margin: 10.3%

Includes contract outfits that perform a variety of services, on a fee basis, for oil and gas operations (except site preparation and related construction activities). Services include, among other things: exploration (except geophysical surveying and mapping); excavating slush pits and cellars; well surveying; cementing, cleaning, bailing and chemically treating wells. Dirty work, but someone has to do it.

19. Wired Telecommunication Carriers

Average Pretax Margin, 2000 to 2009: 10.1%

This industry comprises operators of, or suppliers to, transmission facilities for voice, data, text, sound and video using wired telecommunications. Hey, it's a wired world.

Note: No.1 was not available on the site so I renumbered the sequence. Also there was a separate error in numbering.