Endeavor Real Estate Group unveiled the first public look Friday at a 13-story office tower downtown that it plans to develop for IBC Bank’s new Austin headquarters, and an Endeavor official said the project could break ground in December.

The project, to be known as IBC Bank Plaza, is planned for 500 W. Fifth St., near Republic Square and the downtown post office. The development would include 195,000 square feet of office space, with IBC occupying about 19,000 square feet, including the bank lobby and a drive-through on the ground level, Endeavor and IBC officials said.

IBC Bank is financing the project, the cost of which IBC and Endeavor are not disclosing.

The project is expected to be completed in May 2014. About 165,000 square feet of office space on the upper floors and 11,000 square feet of street-level retail and restaurant space are available for lease, said Jamil Alam, a managing principal with Endeavor. Endeavor and IBC said they already have interest from tenants wanting to pre-lease office space in the building.

Laredo-based IBC Bank has 12 branches in Austin, and the new headquarters would house about 35 people, Shawn Stewart of IBC said.

Since IBC entered the Austin market in 2004, “We have witnessed the rapid evolution of the downtown area into a vibrant urban center reminiscent of some of the nation’s largest cities,” said Bob Barnes, president and CEO of IBC Bank-Austin. “The IBC Bank Plaza will be a perfect addition to the city by providing additional office and retail space to our growing community in one of the most coveted areas of town.”

The building is one of several new office buildings currently planned for downtown. The last high-rise office building to break ground downtown was Cousins Properties Inc.’s Frost Bank Tower, which began construction in late 2001.

Cousins plans to build a 30-story office tower at Third and Colorado streets that would have about 390,000 square feet. Also, Schlosser Development Corp. said it plans to construct two buildings, including a 20-story tower, as part of a corporate headquarters expansion for Whole Foods Market Inc. that would be just east of Whole Food’s current headquarters.

Charles Heimsath, a local real estate consultant, said downtown is the most desirable office location citywide, based on the combination of high average rental rates — $32.66 per square foot — and occupancy of 87.5 percent.

“It is obvious to those that are in the market that we need more Class A office space, and given the long lead time for new construction, this is the perfect time to be planning a new building,” Heimsath said.

Alam said that as downtown continues shifting south and west, “IBC Bank Plaza is uniquely positioned to appeal to both traditional downtown office tenants as well as the creative office class.”

Endeavor’s Travis Dunaway and Jonathan Tate will be handling leasing for IBC Bank Plaza. Dunaway said he thinks there is “strong tenant demand for new, sophisticated and efficient office space” downtown.

The building, designed by Dallas-based HKS, will have balconies overlooking Republic Square park, and the upper floors will have Capitol views. Tenants could begin interior construction on their spaces as early as January 2014, Alam said.

Endeavor, known for retail and mixed-use projects including the Domain and Southpark Meadows, also plans other downtown projects, including one it will partner on with Novare Group/Andrews Urban at the post office site and a 36-story tower with 358 apartments on Bowie Street with partner Lynd Co., a family-owned national real estate company based in San Antonio.

Endeavor and Lynd plan to break ground on the Bowie Street high-rise in September, with the first apartments ready by third quarter 2014. Endeavor plans to move its offices into the building, which will have about 42,000 square feet of office space.