VTech obtained a primary listing on the London Stock Exchange in 1991.

In September 2012 it decided to move its primary listing to the London Stock Exchange.

In 1998 the management attempted to shift the company's head office and primary listing to the USA.

Shell Pakistan has a primary listing on Karachi Stock Exchange.

Its primary listing is in London, and it is not traded in the United States.

The two studies cover only those stocks whose primary listing is on the New York Stock Exchange.

Since shifting its primary listing to London last year, the company has been focusing on mining and shedding unrelated interests.

Its shares have a primary listing on the Tokyo Stock Exchange.

So the company's primary listing truly is in New York, even though its actual shares do not trade there.

Further, these and all other primary listings together account for a tiny percentage of the Philadelphia Stock Exchange's volume.