London (CNN Business) 1. Brace for turbulence: Boeing shares were poised to open lower Monday after a weekend of negative headlines about its 737 Max.

The Wall Street Journal reported Sunday that US federal prosecutors and Department of Transportation officials are scrutinizing the development of the 737 Max, which has been grounded following two deadly crashes.

The newspaper said that a grand jury in Washington, D.C. has issued a subpoena to at least one person involved in the plane's development.

It's not clear whether the probe is connected to an investigation by the Transportation Department's Inspector General into the Federal Aviation Administration's approval of the jets.

The FAA said in a statement that its "aircraft certification processes are well established and have consistently produced safe aircraft designs."

Yet Bloomberg reported that FAA employees warned seven years ago that Boeing had too much sway over aircraft approvals. US auditors had confirmed that the FAA hadn't done enough to "hold Boeing accountable," Bloomberg added.

Shares in Boeing were down nearly 2% premarket. The stock lost 10% of its value last week.

2. German super-bank?: Shares in Deutsche Bank DB Commerzbank CRZBF Shares inandshot higher Monday after the companies confirmed they are discussing a merger.

The merger would help consolidate Germany's crowded retail lending market by creating a single bank with combined assets of €1.9 trillion ($2.2 trillion) and roughly 150,000 employees.

Yet there are doubts that buying its smaller rival will resolve Deutsche Bank's persistent problems with profitability and help it compete with American rivals that have fared much better since the global financial crisis.

Any deal would face scrutiny from regulators and opposition from labor unions in Germany.

Frank Bsirske, head of Germany's Verdi union and a member of Deutsche Bank's supervisory board, spoke out against a merger with Commerzbank and warned it could put more than 20,000 jobs at risk.

"Deutche Bank and Commerzbank do not complement each other," he was quoted as saying during an interview with Suttgarter Zeitung. An international tie-up would make more sense, he added.

Shares in Deutsche Bank increased 3.3% in Frankfurt. Commerzbank stock added 5.7%.

3. Lyft valuation: Lyft is targeting a valuation of up to $23 billion in its initial public offering, according to the Lyft is targeting a valuation of up to $23 billion in its initial public offering, according to the Wall Street Journal

The valuation could change, sources told the newspaper, before shares start trading. The ride-hailing startup announced plans earlier this month to list on the Nasdaq under the stock ticker "LYFT."

Alexandra LaManna, a spokesperson for Lyft, declined to comment.

After years of keeping investors waiting, a stampede of tech startups could hit Wall Street this year. Uber, Airbnb, Slack, Pinterest and Postmates are all expected to go public in 2019.

4. Payments mega-deal: Two of the world's top payments companies are coming together in a $43 billion deal.

FIS FIS WorldPay WP , which provides software for payment processing and other financial services, is buying, which makes technology that supports payments for e-commerce sites.

The new entity, which will have annual revenue of more than $12 billion, will be better placed to serve the world's growing e-commerce industry, the two companies said in a statement Monday.

FIS is offering Worldpay shareholders a mix of cash and stock to make the deal happen. It will assume Worldpay's debt as part of the agreement that values the company at $43 billion.

FIS shareholders will end up holding 53% of the merged company, while Worldpay shareholders will own the remaining 47%. The deal is expected to close later this year.

Prada PRDSY shares plunged as much as 10% in Hong Kong after the company reported 2018 sales and profit figures on Friday that failed to meet analyst expectations.

Crude oil futures dropped 0.7% as OPEC members met with allies including Russia in Azerbaijan. The countries agreed in December to cut oil production by 1.2 million barrels per day from January through June to help support prices.

Saudi Arabia signaled it may need to extend the cuts into the second half of this year, according to Reuters.

6. Earnings and economics: Lumber Liquidators LL Overstock.com OSTK Del Taco TACO andwills release earnings before the open.will follow after the close.

The National Association of Home Builders will release its latest monthly survey of US builders.