JUNE 12–TAIPEI –Taiwan Semiconductor Manufacturing Co. and France’s STMicroelectronics N.V. will join the Philadelphia Semiconductor Index later this month, the Philadelphia Stock Exchange Inc. said in a Web site posting.

This marks the first time non-U.S. companies will be included in the closely watched index, a move that’s likely to boost the stocks of both chipmakers and increase their visibility among a broader range of investors.

Lattice Semiconductor Corp., of Hillsboro, Ore., will be removed from the list when the two new companies are added on June 23.

The changes will leave the index with 18 companies.

The Philadelphia Semiconductor Index is a price-weighted index of companies primarily involved in the design, distribution, manufacture and sale of semiconductors. It includes chip heavyweights like Intel Corp. and Texas Instruments Inc.

In morning trading on the New York Stock Exchange, shares of TSMC climbed 28 cents, or 2.7 percent, to $10.47.

STMicro slipped 43 cents, or 1.9 percent, to $22.35 on the Big Board.

Shares of Lattice fell 27 cents, or 3.1 percent, to $8.48 on the Nasdaq Stock Market