The market for DRAM, a semiconductor, is highly cyclical. Downward pricing pressure is driven by the oversupply of DRAM memory in the market, along with the additional price pressure from PC makers. The price decreases sometimes result in the selling price dipping below production cost, making for a very difficult business environment.
Oversupply is typically catalyzed by manufacturers building multi-billion dollar fabrication facilities (or "fabs") to make these memory devices. However, they operate the facilities at almost 100% capacity to make up the fixed cost of the factory, sometimes creating huge oversupply. DRAM memory is often made on the same types of fabs as NAND flash memory, which is used in devices such as the iPod Nano and Shuffle; hence, the markets for these two memory types are highly correlated.
Micron Technology (MU): 86% of its sales from memory products such as DRAM and NAND in 2006. . It also sources in increasing amount of revenue from complementary metal oxide semiconductorr (or CMOS) image sensors used in digital cameras and other similar devices. Total 2006 revenues were $5.3 billion
Samsung (SSNLF): In 2005, Samsung was the leader in DRAM with sales of $7.4 billion. Its semiconductor division is part of Samsung Electronics, which produced nearly $90 billion in 2006 sales.  Samsung Electronics is itself part of a larger conglomerate, Samsung Group, which had 2005 revenues of $142 billion. 
Elpida Memory (ELPDF): Elpida is a small Japan-based DRAM producer. In 2005, Elpida's DRAM sales were just over $1.7 billion.
Hynix Semiconductor (HXSCL): Hynix was the second largest DRAM supplier in 2005 with sales of $4.1 billion.
Qimonda AG (QI): Qimonda is a major DRAM producer with a 12.6% market share in 2005.