During one very short year, the small, coastal city of Carpinteria has gone from an also-ran to the hottest market around when it comes to new job growth and filling commercial space.

Research by the Business Times and Mark Schniepp’s California Economic  Forecast shows that just two companies — Nusil and Lynda.com are mainly responsible for gobbling up thousands of square feet in Carp, which now is just about as fully leased up as at anytime since the dot-com era.

Nusil, as you might know, is a privately-held producer of silicone products, including some of the most advanced items used by Santa Barbara’s trio of breast implant makers — Johnson & Johnson, Allergan and Sientra.

Lynda.com is a software training company that makes instructional videos that help people learn how to programs ranging from Microsoft Excel spreadsheets to Adobe’s InDesign. A popular course involves learning Apple’s Final Cut Pro, and the company makes money by selling volume subscriptions to UC Santa Barbara and other academic institutions.

Although still privately held, Lynda.com raised an eye-popping $103 million in venture capital in January, fueling an acquisition and potentially signaling that it may follow Facebook and Twitter down the path to an IPO.

This is pretty heady stuff for Carpinteria, the 19th largest city in the Tri-Counties with a population of just 13,000. On any given day, Nusil or Lynda.com could account for a big chunk of the city’s work force.

Though the rise of home-grown Nusil and Lynda.com, a Ventura transplant, has given Carp a big boost, the emergence of one or two large and powerful corporate players in a small community is getting to be a permanent feature of the regional landscape.

Beginning in the mid-1990s, Amgen in Thousand Oaks invested well in excess of $1 billion on a sprawling campus that now employs around 5,000 people. Similarly, Bank of America, formerly Countrywide Financial Corp., came to dominate Simi Valley with its massive home-loan financing operation. Amgen and Countrywide so skewed the area toward non-durables manufacturing and financial services that economists raised some serious red flags about over-concentration in a single industry. Any major layoffs at Amgen or Bank of America send shock waves through the East Ventura County economy.

Meanwhile, Oxnard frets about the future of just one player, Haas Automation, which has not yet worked out whether it will expand Ventura County or try Texas or the Carolinas for a new machine tool operation.

Meanwhile, downtown Santa Barbara is now linked in part to the success of audio gear maker Sonos, Santa Maria depends heavily on aircraft seat maker C&D Zodiac and San Luis Obispo increasingly has linked its fortunes to the success of business management software firm MindBody, which is building a $20 million  campus near the city’s airport.

While expansion moves at Nusil and the big capital raise at Lynda.com have filled Carp’s office space and its restaurants, there are risks to tying your future  to a handful of large incumbents. Simi Valley is still smarting over the departure of Farmer’s Insurance, which left for the San Fernando Valley three years ago, taking 1,200 jobs and leaving behind a large building which remains empty.

And to bring the column back to full circle, the next question for Caprinteria is whether another big incumbent, CKE Restaurants, will stay or go when its lease is up. CKE’s headquarters represents as much as 20 percent of Carp’s office space, and CEO Andy Puzder has not been shy about kvetching about the high cost of doing business in California. But the company recently has stated that while its fast-food restaurants are expanding faster in Texas than in the Golden State, it won’t break its lease, which is up in 2015, to move elsewhere.

The bottom line is that betting your future on one or two large companies has its share of risks. But that seems to be in the DNA of many of the region’s cities, and Carpinteria is no exception.

• Contact Henry Dubroff at hdubroff@pacbiztimes.com.