Alexander & Baldwin Inc. has finished a homecoming of sorts.

The local real estate investment firm announced Tuesday that it sold its last commercial property on the mainland.

Honolulu-based A&B said the sale was a warehouse complex in Sparks, Nev., near Reno for $38.3 million Friday, and it ended a strategy the company began in 2012 to patiently sell 24 mainland commercial properties and reinvest proceeds in Hawaii real estate.

Sparks Business Center was the last piece of A&B’s mainland real estate portfolio, and followed a flurry of six mainland property sales since late last year.

In all, A&B said, proceeds from the 24 sales since 2012 totaled about $600 million.

The company has used that revenue to help fuel nearly $1.8 billion in acquisitions of Hawaii commercial property, largely retail real estate, in the same period.

“The last six years have been the most active period of acquisitions in the company’s history,” A&B President and CEO Chris Benjamin said in a statement.

Those acquisitions included 90 percent of the retail buildings in Kailua along with Manoa Marketplace, Pearl Highlands Center, Waianae Mall and a $254 million deal for three shopping centers bought just last month from a California company.

The purchases last month were Laulani Village on Oahu, Pu‘unene Shopping Center on Maui and Hokulei Village on Kauai.

A&B also helped pay for those three retail centers by selling four Hawaii real estate assets — the Judd and Stangenwald office buildings in downtown Honolulu, land under a Kaiser Permanente clinic in Wailuku and a parcel in Kihei — for a combined $39 million.

Using proceeds from selling one property to buy another allows A&B to defer paying taxes on such sales. The company routinely employed the strategy to buy properties and sell them after improving leasing income.

In 2012 A&B’s commercial real estate portfolio was a fairly balanced mix of office, retail and industrial properties — 23 on the mainland and 22 in Hawaii. The mainland assets comprised 6.5 million square feet of leasable space and generated $36 million in net operating income, compared with 1.4 million square feet and $23 million for the Hawaii properties.

Today the portfolio includes more than a dozen retail centers along with several industrial properties in Hawaii with 3.4 million square feet of leasable space.

Concentrating all its commercial property in Hawaii with a retail emphasis fit into A&B’s conversion last year from a traditional corporation into a real estate investment trust, or REIT, focused on Hawaii retail property. As a REIT, A&B is entitled to federal tax breaks but must convey at least 90 percent of profits from the properties to shareholders.

A&B, which originated as a sugar cane plantation operator in 1870, also is involved in residential and resort development, owns Oahu road paving contractor Grace Pacific and is the state’s fourth-largest private landowner with 87,000 acres of mostly farmland mainly on Maui and Kauai.