As of Tuesday, online printing company Vistaprint and computer hardware and IT services retailer PC Connection had received licenses to collect sales taxes on transactions with Pennsylvania customers, according to the department.

Company representatives did not immediately return calls for comment.

Thirty-eight of the top 50 online retailers, or 76 percent, already collect sales taxes in Pennsylvania, according to the department. It based the analysis on matching Internet Retailer magazine's Top 500 retailer list to its database of companies holding a sales tax collection license.

In December, the state said it would enforce sales tax collection by online retailers with a physical presence in Pennsylvania. The department also told online retailers that in-state advertising affiliates would be counted as a presence and would require tax collection.

The Revenue Department initially gave retailers until Feb. 1 to comply, but it pushed that deadline back to September to give small retailers more time to meet the policy.

With the two additions, 80 percent of the top 50 online retailers collect sales taxes in the state. However, companies that don't collect include some of the largest online retailers, such as Seattle-based Amazon.com Inc. It has five warehouses in Pennsylvania, including three in Cumberland and York counties.

The Corbett administration has pushed the online sales tax policy as a means to level the playing field for bricks-and-mortar retailers, who say they're at a 6 percent disadvantage. The U.S. Supreme Court ruled that states only can collect sales taxes from companies with a physical presence, which means online, catalogue and other remote retailers don't charge customers sales tax. Interstate commerce is Congress' domain.