St. Anton Partners has grown beyond its roots as a developer of affordable housing.

Steve Eggert and Peter Geremia founded the firm in 1995 and have built more than 6,000 units of housing. About five years ago, they made a big push to broaden their focus to include more market-rate and mixed-income developments.

“We really identified the need to expand beyond affordable housing,” says Eggert. “We felt it was important to have a more balanced portfolio.”

The firm now has more than 2,000 market-rate or mixed-income units completed or under construction.

Its most notable project is just getting under way. St. Anton is working with Facebook to build a 394-unit multifamily housing community within walking distance of the social media giant’s Menlo Park, Calif.-headquarters.

At more than 630,000-square-feet, Anton Menlo is one of the largest new construction rental residential projects in the state.

The developers first “friended” Facebook when the internet company was planning a new campus and one of the conditions of approval for the offices was to provide 15 affordable housing units.

St. Anton had assembled a nearby 9.8-acre site to build its multifamily housing community. It has agreed to include Facebook’s 15 units in its development. In addition, the firm is creating another 38 units of affordable housing in order to receive a density bonus for the project, resulting in a total of 53 apartments reserved for residents earning no more than 80 percent of the area median income.

A 53-unit affordable housing project would be a big deal on its own in the pricey Silicon Valley, but in this case the apartments will be integrated into the larger Anton Menlo development, notes Eggert, a trained tax attorney and former Army Ranger.

The $120 million development will be conventionally financed, with Facebook making a contribution to satisfy its affordable housing requirement.

The project’s proximity to Facebook will also mean that many of the internet company’s employees will likely make the new development home once it is completed in about 24 months.

St. Anton has held focus groups with Facebook workers to learn their housing needs and gain guidance.

“It’s all about convenience,” says Eggert. “Facebook employees are very hard working. They work long hours and like the convenience.”

Designed by KTGY Group with young professionals in mind, the new development will include a “grab-and-go” convenience store, coffee shop, a brew pub for residents, and concierge services.

Eggert also learned that the employees like pets, so Anton Menlo will include a pet spa with a station where residents can drop off their dogs to be picked up by an off-site doggy day-care service.

The community includes 35 studios, 208 one-bedroom, 139 two-bedroom, and 12 three-bedroom apartments.

Although the new project has attracted the most media attention, it is not the only development that Sacramento, Calif.-based St. Anton is working on in the state.  The firm is No. 6 on this year’s Affordable Housing Finance list of Top 50 developers.

Recent projects have included conventionally financed market-rate deals like Anton Menlo and 80/20 projects, where 80 percent of the units are market-rate apartments and 20 percent are affordable in order to qualify for bond financing. The firm also continues to be involved in larger affordable housing projects, including a 232-unit, 4 percent low-income housing tax credit property that’s under construction in Anaheim.