What you need to know on Wall Street today

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

There have historically been two dominant tribes on Wall Street. There's the sell side, the investment banks, which, as their name suggests, mostly sell stuff. There's also the buy side, the fund managers, which mostly buy stuff.

A third group — including stock exchanges, trading platforms, clearinghouses, and data providers — helps facilitate transactions between the two dominant groups.

Those institutions are sometimes called the "pipes and plumbing of global finance." If you needed a reminder, pipes and plumbing aren't sexy, and neither is this third group. That's beginning to change.

Britain's two-year exit process from the European Union began Wednesday when Prime Minister Theresa May triggered Article 50. Here's what you need to know:

• Article 50 has been triggered
• Everything you need to know about what happens next
• The 11 most important people deciding Britain's Brexit fate
• Everything you need to know about post-Brexit immigration in 5 minutes
• Goldman Sachs reassures staff over Brexit in voicemail as it "intensively" prepares contingency plans
• The EU has officially blocked a £22.5 billion mega-merger between the London Stock Exchange and Deutsche Börse

In other news, Santander just got hit hard for approving thousands of subprime auto loans. Bloomberg LP, the financial data giant, is shaking up its trading unit. Steve Wynn just lost his slander appeal against hedge fund manager Jim Chanos. And one chart explains why David Einhorn is the 2nd activist to target GM in 2 years.

In markets news, there's been a "stunning" shift in the US economy since Trump's election. A hedge fund manager who retired at 36 is sounding the alarm on the Trump trade. The Fed is keeping a close eye on the "Trumpcare" failure

And the Trump administration is judging itself on the wrong market, according to Business Insider's Pedro da Costa.

In deal news, the startup that teaches you how to cook, Blue Apron, has hired bankers for an IPO in 2017. There's a way to invest in a cleaner environment, and the market is booming.

In tech news, a revolution that's underway in healthcare could have us thinking about X-rays the same way we think of iPhones.

President Trump's son-in-law, Jared Kushner, is caught between two worlds, and his friends are cutting ties.

Lastly, here are the five most outrageous timepieces revealed at the world's biggest watch exhibition.

Here are the top Wall Street headlines from the past 24 hours.

Wells Fargo agrees to pay $110 million to settle customer accounts lawsuit - Wells Fargo has agreed to pay $110 million to settle a class-action lawsuit over up to 2 million accounts its employees opened for customers without getting their permission, the bank announced Tuesday.

BlackRock plans major changes to its active stockpicking business - BlackRock on Tuesday said it would dramatically recast a portion of its fund management operations, conceding that the business of picking stocks has grown increasingly competitive.

Buyers are rushing into the housing market in anticipation of higher interest rates - Some prospective homebuyers are speeding up the process in anticipation of higher interest rates, according to the National Association of Realtors. 

A top Goldman Sachs dealmaker explains the No. 1 lesson she's learned in her career - The truth can be a tough pill to swallow. But ignoring the truth, in many cases, can make things a lot worse.

A doctor who watched a young White House aide be destroyed by MS 40 years ago now has an approved drug to treat it - Forty years ago, one of Dr. Stephen Hauser’s first patients was a young Harvard Law School graduate and White House aide with a case of multiple sclerosis that raced like a brush fire through her brain.

Toshiba's US nuclear unit files for bankruptcy - Toshiba Corp's US nuclear unit Westinghouse filed for Chapter 11 protection from creditors on Wednesday, as its Japanese parent seeks to limit losses that threaten its future.

Live like a Russian billionaire in this over-the-top Long Island mansion, which is back on the market for $85 million - Whether you want to relive the glamour of the Roaring Twenties or just want to see what life is like for a Russian billionaire, this $85 million property on New York's Long Island has got you covered.