It’s been a rough week for Facebook. Its stock price has tumbled. Lawsuits have been filed. And now it looks like four of the top market makers for the initial public offering—Knight Capital, Citadel Securites, UBS, and Citi’s Automated Trading Desk—are going to collectively lose more than $100 million on the deal. The culprit was a technical glitch that delayed Facebook’s market debut by about 30 minutes, forcing thousands of orders from clients to be delayed. The Securities and Exchange Commission, along with the Financial Industry Regulatory Authority, is scrutinizing whether the IPO was handled properly.