Wall Street stock futures are slightly higher Friday in premarket trading, adding to Thursday’s big gains as the market regains its composure after a data-driven roller-coaster.

Today’s must-read story is by Fortune‘s Jonathan Vanian and it looks at United Airlines’ offer of frequent flier miles to hackers who can weed out bugs in the company’s websites and mobile apps.

Here’s what else you need to know about:

1. SABMiller buys another craft brewer, this time in London

SABMiller said Friday it’s buying Meantime, the largest craft brewer in London, in the latest example of global brewing giants snapping up the minnows who are draining away their market share. The logic for the acquisition is the same as in the U.S.. In a national market that grew by less than 1% last year, Meantime’s sales grew 58%.

2. The bubble in crazy prom spending may be about to burst.

Yes, some teens still stage elaborate ‘promposals’ and buy $1400 prom dresses — but here’s a surprise: families are spending 6 percent less than they spent last year and 19 percent less than they spent in 2013. In fact, high school prom is now actually something of a bargain, according to Jay Zagorsky, economist and research scientist at The Ohio State University.

3. Petrobras earnings

Petrobras, the Brazilian state-owned energy company, reports first-quarter results this afternoon and the company’s revenue and earnings are both expected to decline year-over-year. Like most of its oil and gas rivals, Petrobras has suffered from the decline in global crude oil prices. The company is also at the center of a major corruption scandal, which recently led to the conviction of a former Petrobras executive on money laundering charges.

4. Mobile operators getting ready to block ads on their networks

Several mobile operators plan to block advertising on their networks, setting the stage for a battle with digital media companies such as Google and Yahoo, the Financial Times reports. That could have profound consequences for the $69 billion global market for mobile ads that was at the heart of this week’s $4.4 billion takeover of AOL by Verizon.

5. Blues legend B.B. King is dead at 89

The world has got the blues. B.B. King died peacefully in his sleep at his home in Las Vegas. The one-time farmhand popularized blues music and influenced a generation of musicians with his heartfelt vocals and soaring guitar on songs such as “The Thrill Is Gone.”
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