The investment banking industry has come under criticism for a variety of reasons, including perceived conflicts of interest, overly large pay packages, cartel-like or oligopolic behavior, taking both sides in transactions, and more. About the book: https://www.amazon.com/gp/product/0470222794/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0470222794&linkCode=as2&tag=tra0c7-20&linkId=122da9b4ed66d7e4eb80287e1bee5b2a
Investment banking has also been criticized for its opacity.
Conflicts of interest may arise between different parts of a bank, creating the potential for market manipulation, according to critics. Authorities that regulate investment banking (the FSA in the United Kingdom and the SEC in the United States) require that banks impose a "Chinese wall" to prevent communication between investment banking on one side and equity research and trading on the other. Critics say such a barrier does not always exist in practice, however.
Conflicts of interest often arise in relation to investment banks' equity research units, which have long been part of the industry. A common practice is for equity analysts to initiate coverage of a company in order to develop relationships that lead to highly profitable investment banking business. In the 1990s, many equity researchers allegedly traded positive stock ratings for investment banking business. Alternatively, companies may threaten to divert investment banking business to competitors unless their stock was rated favorably. Laws were passed to criminalize such acts, and increased pressure from regulators and a series of lawsuits, settlements, and prosecutions curbed this business to a large extent following the 2001 stock market tumble after the dot-com bubble.
Philip Augar, author of The Greed Merchants, said in an interview that, "You cannot simultaneously serve the interest of issuer clients and investing clients. And it's not just underwriting and sales; investment banks run proprietary trading operations that are also making a profit out of these securities."
Many investment banks also own retail brokerages. During the 1990s, some retail brokerages sold consumers securities which did not meet their stated risk profile. This behavior may have led to investment banking business or even sales of surplus shares during a public offering to keep public perception of the stock favorable.
Since investment banks engage heavily in trading for their own account, there is always the temptation for them to engage in some form of front running -- the illegal practice whereby a broker executes orders for their own account before filling orders previously submitted by their customers, there benefiting from any changes in prices induced by those orders.
Documents under seal in a decade-long lawsuit concerning eToys.com's IPO but obtained by New York Times' Wall Street Business columnist Joe Nocera alleged that IPOs managed by Goldman Sachs and other investment bankers involved asking for kickbacks from their institutional clients who made large profits flipping IPOs which Goldman had intentionally undervalued. Depositions in the lawsuit alleged that clients willingly complied with these demands because they understood it was necessary in order to participate in future hot issues. Reuters Wall Street correspondent Felix Salmon retracted his earlier, more conciliatory, statements on the subject and said he believed that the depositions show that companies going public and their initial consumer stockholders are both defrauded by this practice, which may be widespread throughout the IPO finance industry. The case is ongoing, and the allegations remain unproven.
Investment banking is often criticized for the enormous pay packages awarded to those who work in the industry. According to Bloomberg Wall Street's five biggest firms paid over $3 billion to their executives from 2003 to 2008, "while they presided over the packaging and sale of loans that helped bring down the investment-banking system." 
The highly generous pay packages include $172 million for Merrill Lynch & Co. CEO Stanley O'Neal from 2003 to 2007, before it was bought by Bank of America in 2008, and $161 million for Bear Stearns Co.'s James Cayne before the bank collapsed and was sold to JPMorgan Chase & Co. in June 2008.
Such pay arrangements have attracted the ire of Democrats and Republicans in Congress, who demanded limits on executive pay in 2008 when the U.S. government was bailing out the industry with a $700 billion financial rescue package.
Writing in the Global Association of Risk Professionals, Aaron Brown, a vice president at Morgan Stanley, says "By any standard of human fairness, of course, investment bankers make obscene amounts of money."