The following IPOs are expected to price this week:

KiOR (KIOR), which is developing a platform to convert non-food biomass into fuel blendstocks, plans to raise $200 million by offering 10 million shares at a price range of $19 to $21. At the mid-point of the proposed range, KiOR will command a market value of $2.3 billion. KiOR, which was founded in 2007, plans to list on the NASDAQ under the symbol KIOR. Credit Suisse, UBS Investment Bank, and Goldman, Sachs & Co. are the lead underwriters on the deal.

Pioneer Power Solutions (PPSI), which sells electrical transformers to niche markets in North America, plans to raise $21 million by offering 2.3 million shares at a price range of $8 to $10. At the mid-point of the proposed range, Pioneer Power Solutions will command a market value of $68 million. Pioneer Power Solutions, which was founded in 1995, booked $55 million in sales over the last 12 months. The Fort Lee, NJ-based company plans to list on the NASDAQ under the symbol PPSI. Oppenheimer & Co. is the lead underwriter on the deal.

Stewart & Stevenson LLC (SNS), which offers custom equipment for unconventional drilling to the oil & gas industries, plans to raise $240 million by offering 16 million shares at a price range of $14 to $16. At the mid-point of the proposed range, Stewart & Stevenson LLC will command a market value of $1 billion. Stewart & Stevenson LLC, which was founded in 1902, booked $971 million in sales over the last 12 months. The Houston, TX-based company plans to list on the NYSE under the symbol SNS. J.P. Morgan, Goldman, Sachs & Co., and Citi are the lead underwriters on the deal.

Vanguard Health Systems (VHS), which operates 26 acute care and specialty hospitals in five US states, plans to raise $550 million by offering 25 million shares at a price range of $21 to $23. At the mid-point of the proposed range, Vanguard Health Systems will command a market value of $1.6 billion. Vanguard Health Systems, which was founded in 1997, booked $4.3 million in sales over the last 12 months. The Nashville, TN-based company plans to list on the NYSE under the symbol VHS. BofA Merrill Lynch, Barclays Capital, and Citi are the lead underwriters on the deal.

Last week, there were 4 IPO pricings. Bankrate, Inc. (RATE), which is a leading publisher, aggregator and distributor of online personal finance content, was the week's winner, ending up 2% from its IPO price.