Entegris Inc. agreed to acquire ATMI Inc. in a deal valued at $1.15 billion, combining suppliers of semiconductor materials to seek larger orders.

ATMI shareholders will receive $34 in cash for each share of common stock they own, the companies said in a statement today. The price represents a premium of 26.3 percent over ATMI’s closing price on Feb. 3.

Suppliers for the semiconductor industry are under pressure to merge because there are fewer big customers to go around. Manufacturers such as Samsung Electronics Co., Taiwan Semiconductor Manufacturing Co. and Intel Corp. increasingly dominate spending on equipment, reducing the number of major contracts available, according to Patrick Ho, an analyst for Stifel Nicolaus & Co.

In November, Danbury, Connecticut-based ATMI hired Barclays Capital to explore strategic options after demand for the company’s materials waned in some markets such as microelectronic wafers.

Entegris, a maker of liquid and gas filters and purifiers for the semiconductor industry, said today’s deal will immediately boost its adjusted earnings per share. The purchase is valued at $850 million when taking into account cash acquired, including net cash proceeds of $170 million from the sale of ATMI’s LifeSciences business, Entegris said.

Entegris rose 13 percent to $11.60 at 9:42 a.m. in New York, while ATMI jumped 26 percent to $33.82. Entegris advanced 26 percent last year, and ATMI added 45 percent.

ATMI Chief Executive Officer Douglas Neugold had been working to cut costs after facing a shrinking customer list. Income from continuing operations in the fourth quarter fell 46 percent to $6.4 million, the company said in separate statement today.