What you need to know on Wall Street right now

Welcome to Finance Insider, Business Insider's summary of the top stories of the past 24 hours.

Wells Fargo CEO John Stumpf is in front of the Senate Banking Committee to answer questions about fraudulent accounts opened by Wells employees.

Here's what you need to know:

• Hillary Clinton on Tuesday published an open letter to Wells Fargo customers, slamming the bank's illegal account openings and outlining what should happen next.
• Stumpf said at the hearing that the problems with opening accounts were not a systemic issue created by the upper levels of the firm. "I do want to make it clear that there was no orchestrated effort, or scheme as some have called it, by the company," said Stumpf.
• The bank is expanding its review for possible improper accounts to 2009 and 2010.
• Stumpf said the business was dealing with the issue for a number of years before he knew of the issue. "If I could turn the clock back, I, we all, wish we had done something earlier," said Stumpf.
• Sen. Elizabeth Warren lit into Stumpf, saying he had exemplified "gutless leadership" and he should be personally "criminally investigated" for the scandal. Sen. Jeff Merkley also called for Stumpf's resignation.
• You can follow our live coverage here.
• Here's Business Insider's Linette Lopez on why people on Wall Street cheat over and over again.

A changing of the guard is taking place at Goldman Sachs. The securities division, which houses the bank's equities and fixed income, currencies, and commodities units, has seen at least 18 partner-level departures from key roles in the US and Europe in 2016. You can read all about the quiet shake-up taking place at the bank here.

Once again, we've asked some of the sharpest strategists, economists, and reporters for one chart that's at the top of their minds right now. Here are the most important charts in the world from the brightest minds on Wall Street.

In other news, Obamacare and EpiPens are causing an inflation problem. Allergan could pay up to a 1,800% premium to acquire a tiny pharmaceutical company. West Virginia is accusing Mylan, the maker of the EpiPen, a life-saving autoinjector used to treat severe allergic reactions, of Medicaid fraud.

And a group of drug companies just laid out a plan to combat superbugs.

The next big tech IPO of the year is starting to look like a bummer, and Comcast plans to launch its own wireless service in 2017.

Lastly, here are the 25 coolest new businesses in New York City.

Here are the top Wall Street headlines at midday:

Jefferies just reported a big jump in profits - Investment bank Jefferies Group on Tuesday reported a jump in third-quarter profits, driven by strong revenue in its fixed income trading business.

SeaWorld is tumbling after slicing its dividend - SeaWorld shares are sliding after the company cut its dividend.

One of Warren Buffett's investing gurus was named to JPMorgan's board - JPMorgan Chase on Tuesday said it elected Todd Combs, a stock-picking deputy of billionaire investor Warren Buffett, to its board of directors.

SOROS: The refugee crisis 'has no simple solution' - The refugee crisis is at the top of George Soros' agenda.

GUNDLACH: The Fed won't raise rates on Wednesday - Jeff Gundlach, the CEO of DoubleLine Capital, thinks the Federal Reserve will be on hold in September.

T. Boone Pickens says 'know your limitations' and do only what you are good at - The 88-year-old founder of BP Capital Management doesn't pretend he's someone he's not.

JPMorgan takes stake in InvestCloud - JPMorgan said it had hired and would take a stake in InvestCloud, which provides software that makes online transactions easier for customers with banking and investment accounts.

Lloyds is hiring a fintech 'tsar' - here is the job description - Lloyds Bank is looking for a "Head of FinTech Discovery," as part of its £1 billion digital transformation plan over three years.

Italy is a 'systemic risk' and could become investors' new obsession - For the past several years, investors have been held hostage by the threat of Greece defaulting on its debt and eventually leaving the eurozone.

Americans wasted $2.1 billion on premium gas during the last year - Hello America! You do not need to put premium fuel in your vehicle if the manufacturer does not require it.

China's Tesla killer just raised $1 billion for its electric car project - here's everything we know about it - Chinese company LeEco is making serious moves to compete with Tesla.