The Trans-Alaska Pipeline System has brought billions of dollars in Alaska oil to market -- and it could bring millions in funds to towns it passes, in a tax case flowing from the pipeline’s assessed value.

Four days of testimony wrapped up in the case Thursday, leaving the State Assessment Review Board to determine TAPS’s assessed value for 2014.

In 2013, that assessment was $11.9 billion. Attorneys representing the Fairbanks-North Star and North Slope boroughs, as well as the City of Valdez, say the 2014 assessment should be $13.7 billion.  The line runs through those three localities, enabling them to collect property taxes.

"It's important to our communities, to our police, to our fire departments, to the people in these communities, that you get it right -- so I'm here to ask that you do,” said Robin Brena, an attorney for the local governments.

Brena’s clients split $2.5 million in settlement money after the Alaska Supreme Court upheld a Superior Court’s ruling that the 2010 value of the pipeline was $10 billion.

Although Brena criticized the state’s assessment of $5.7 billion and the oil industry’s estimate of $2.7 billion for the 2014 assessment, lawyers for the state and the oil companies say the 2010 numbers are out of date.

“It's a depreciating asset -- now that it is eight years older, reserves have declined,” said oil industry attorney James Torgerson. “It is a depreciating asset that is serving a declining field, and the throughput has declined.”

Torgerson adds that the boroughs and Valdez are basing some of their numbers on the value of the pipeline when it was originally constructed in the 1970s.

For Jim Mosely, SARB's chair, the case represents a balancing act.

"Because there are three different opinions, we end up trying to choose the one that is the most credible,” Mosely said.

The board has until June 1 to render an opinion.