The oil refinery deal between Sunoco Inc. (SUN) and Holly Corp. (HOC) is unlikely to trigger a string of similar transactions, even though it signals that asset values have hit a 15-year low.

Sunoco has agreed to sell its Tulsa, Okla., refinery to Holly for $65 million, a price tag that covers the cost of an oil product terminal and land but barely takes the refinery units into account.

The deal values the facility at $228 per complexity barrel, an indicator used by analysts to compare deals on a standardized basis. By this measure, the Tulsa plant's valuation is less than half of that for a Louisiana refinery, which was sold in July 2008 before the credit crisis reached fever pitch and the global economic downturn came into full force. Today's valuation for Sunoco's Tulsa refinery is well below that seen for refining assets at their high in 2007 and more in line with 1990's prices.

Even with these low prices, which come on the back of weak profits, there's a reluctance to strike deals. After several years of historically high margins, the refining sector began to slump in late 2007 as crude oil prices, refiners' biggest cost, began their meteoric rise and as demand for crude-derived products such as diesel and gasoline fell. As in many other parts of the economy, buyers and sellers have had difficulty agreeing on price, effectively freezing the dealmaking landscape.

This time around, sellers have little incentive to take a sub-par price for their refineries. In the 1990s, refineries were often sold to comply with antitrust regulations as oil companies merged. Without this catalyst, refiners are likely to wait out the downturn and hold onto their refineries, even underperforming ones.

Buyers, too, may be reluctant to do deals, even in a market that favors them. Many refiners, like companies in many other industries, are holding tight to cash reserves. Plus, those with cash on hand say there aren't many must-have assets for sale.

The Tulsa refinery has long been considered to be a bottom tier refinery, and it's unlikely that other refineries will sell at a lower price per barrel than this one. The plant requires at least a $150 million investment to comply with environmental regulations. The refinery produces a limited slate of products and doesn't have access to a wide range of crude supplies that proximity to an ocean port would offer. However, it's near the oil hub of Cushing, Okla., which currently has an oversupply of crude oil on offer, although that's not always the case.

Last year, Sunoco put the 85,000-barrel-a-day refinery up for sale and by December disclosed that it would convert the facility into an oil product terminal if it couldn't find a buyer.

That announcement made the refinery ripe for lowball offers. Other refineries up for sale, including Valero Energy Corp.'s (VLO) in Aruba and Western's Refining Inc. (WNR) Yorktown, Va., should be able to fetch a better price simply because those companies aren't compelled to sell.

A threat of a refinery closure from Exxon Mobil Corp. (XOM) in 1992 allowed formerly independent refiner Tosco Corp. to purchase the largest refinery in the U.S. East Coast at a price that set the floor for refinery assets at the time. That deal encouraged other independent refiners to go on buying sprees as integrated oil companies tried to sell off their plants.

Holly's purchase is similar to Tosco's, said IHS Herold analyst John Parry.

"It should tend to lower seller's expectations for what they can get," Parry said.

-By Susan Daker, Dow Jones Newswires; 713-547-9208; susan.daker@dowjones.com