Shell, Chevron, Phillips 66 and Petro-Canada each notified customers of updates to previously issued price change notices. These either combine two smaller price changes into one larger change effective on a single date later in May to lessen administrative burden, or announce a larger price change that replaces a previously announced one. Shell will raise prices on finished lubricants by up to 13 percent effective May 29. Chevron will raise prices by up to 14 percent on lubricating oils and greases effective May 29. Phillips 66 will increase finished lubricant prices by up to 14 percent effective May 29. Petro-Canada will increase prices on finished products by up to 14 percent effective May 21.