Investors bid up shares of Alexander & Baldwin Inc. stock on Friday a day after the Honolulu firm announced plans to spin off subsidiary Matson Navigation Co. as a separate publicly owned company.

A&B’s stock surged $6.33, or 17 percent, to $44.39. That was up from Thursday’s close at $38.06 before the company’s announcement.

The company’s stock opened Friday trading at $42.61 on the New York Stock Exchange, fell to $41.27 shortly after the market opened and peaked at midday at $45.23.

The surge followed smaller gains since A&B stock drifted down to a 52-week low of $33.16 on Nov. 25.

Friday’s closing price was about a dollar below where the stock closed on March 31, the day before activist investor and New York hedge fund manager Bill Ackman bought a 10 percent stake in A&B, a move that ignited speculation that A&B might be broken apart.

A day after Ackman’s purchase was disclosed, A&B stock surged 19 percent to a 52-week high of $54.47 from $45.65 the day before.

A&B held a conference call with Wall Street analysts Friday before the stock market opened to explain plans for the separation, which will lead to a separate stock for Matson traded on the NYSE.

A&B says splitting off Matson will result in better operation of both companies and attract more focused investors and stock analysts that help boost shareholder value.

Shareholders of A&B stock will receive an equal number of new Matson shares under the separation plan. Prices for Matson stock will be determined by the market at the time it is created.