It's a bad day for dealmakers on Wall Street

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Finance Insider is Business Insider's midday summary of the top stories of the past 24 hours.

Finance Insider is Business Insider's midday summary of the top stories of the past 24 hours.

It is a bad day for dealmakers on Wall Street.

The Pfizer-Allergan merger, a deal that would have been worth $160 billion, has officially been scrapped.

Here's what you need to know:

• Six advisory banks have lost out on more than $200 million in fees. 
• Numerous hedge funds that had invested in Allergan have taken a hit. 
• Allergan's CEO has called the Treasury's measures to target inversions "un-American."
• The Treasury's measures could put a chill on the broader M&A market. 
• A number of M&A-focused investment banks have seen their share price drop sharply. 
• Pfizer has been left in the lurch ― here is what might happen next. 

To make matters worse, the Department of Justice has filed an antitrust lawsuit to block Halliburton from buying Baker Hughes.

Elsewhere, hedge fund billionaire Bill Ackman, founder of $12 billion Pershing Square Capital, hosted a quarterly conference call this morning.

"We've made a number of mistakes in Valeant that have required some soul-searching," he said. 

Democratic Presidential candidate Bernie Sanders struggled to explain his Wall Street plans in an uncomfortable interview. Democratic rival Hillary Clinton later said that Sanders "hadn't done his homework."

The Obama administration is about to unveil a new rule that impacts $12 trillion of your money, and JPMorgan CEO Jamie Dimon would like everyone to quit bashing big banks. 

And watch out meat eaters: beef is going to be historically expensive. 

Here are the top Wall Street headlines at midday:

Tiger Global's hedge fund has suffered paper losses of more than $1 billion this year - Tiger Global Management's hedge fund has fallen 22% and suffered paper losses of more than $1 billion in the first quarter.

The US government has a $20.4 trillion retirement problem - The US government has nowhere near enough money to pay retirees.

Verizon just bought a big stake in a $650 million video company popular with teens - Verizon has made another big move to grab teen eyeballs by agreeing to buy a 24.5% share in AwesomenessTV, in a deal which values the video powerhouse at $650 million.

Ray Dalio explains the biggest lessons he's learned since implementing his 10-year plan to turn over the reins of the world's biggest hedge fund - Bridgewater Associates — the world's largest hedge fund, with $169 billion in assets under management — is in the midst of a major leadership transition.

A lot of people are going to get rich(er) at these small Wall Street firms - It's been a tough first quarter for mergers and acquisitions (M&A) bankers, but a handful of firms have managed to keep busy.

It looks like China is about to squash a $7 billion luxury industry - A new Chinese fee on packages purchased abroad may bring down a multibillion-dollar "gray market" for luxury goods in the country.

Tesla is in danger of becoming the new Saturn - Tesla — for all of its innovation and master plans to upend driving — could end up becoming something ordinary.