Shortly after, Phillips 66 announced that its Pure Performance 600N posting would be edging up 16 cents/gal to $3.15/gal, with an effective date of July 15.

So far, no other price revisions have emerged, but it was heard that other suppliers were carefully assessing the market situation.

The heavy-viscosity grades, both in the Group I and II categories, remain very tight on healthy demand and lower yields at a number of plants, according to sources. The snug conditions have also led to a reduction in exports of the 600 grade, sources added.

The mid- and light-vis grades are more readily available, and prices have seen fewer fluctuations in recent weeks.

The fresh increases come on the heels of a previous round of price hikes which, for the most part, lifted postings of the heavy-vis cuts.

In the Group I category, producers increased their heavy-vis grades and bright stock by 10 cents per gallon between June 19 and July 1.

In the Group II segment, suppliers also raised several grades in June, but the amount of the increases varied depending on the cut and the seller, ranging between 8 cents and 19 cents per gallon.

Bright stock continues to enjoy steady requirements, while demand for other Group I grades appears to have slowed slightly, sources admitted.

A trading group was heard to have imported a bright stock cargo of European origin for blending in the U.S. Gulf, and also moved some product to Mexico, a market source said. A second small parcel of imported product was also understood to have been sold to Mexican players.

Mexican buyers were said to have been on the lookout for additional cargoes of Group I and II mid-viscosity cuts because of a production hiccup at Petroleos Mexicanos’ (Pemex) Salamanca base oil plant, but the problem has since been resolved, according to sources.

Meanwhile, crude oil prices continued on a somewhat erratic course, with values dropping more than 2 percent and then jumping back up on Tuesday as investors weighed the details of an agreement between several world powers and Iran that is intended to remove sanctions on Iranian exports and curb Tehran’s nuclear program.

West Texas Intermediate (WTI) futures settled on the CME/Nymex at $53.04 per barrel on July 14, up 71 cents per barrel from their July 7 settlement of $52.33 per barrel.

Brent crude was trading around $58.51 per barrel on the CME on July 14, up $1.66 per barrel from $56.85 per barrel a week ago.

Historic U.S. posted base oil prices and WTI and Brent crude spot prices are available for purchase in Excel format.