Several U.S. drug companies, including Pfizer and Merck, have indicated they will not acquiesce with an investor campaign aimed at forcing drug manufacturers to disclose more information about when and why they raise prices. In October, a group of institutional investors submitted shareholder proposals asking 11 U.S. drug companies to issue reports listing average annual price increases for their top-selling drugs between 2010 and 2016, and to state the rationale for the increases. The investors asked the companies to include the proposals on proxy ballots that will be put to shareholder votes at annual meetings this spring. But 10 of the companies plan to omit the drug-price transparency proposals from their proxy ballots, generally on the grounds that they would interfere with "ordinary business," according to company documents filed with the Securities and Exchange Commission (SEC). The SEC notified 10 companies that it will not pursue any enforcement actions if the companies exclude the drug-price proposals. The investor group withdrew the transparency proposal it had submitted to the 11th drug company, Regeneron Pharmaceuticals, because the company said it has not raised the prices of its drugs and shared information about its approach to drug pricing, according to a spokeswoman for the Interfaith Center on Corporate Responsibility, which submitted the shareholder proposals.