CNBC's Week in Review

It was a news-filled week for the markets and the business world in general: the return of market volatility, a worrisome report from the world’s most famous investor, oil price spikes and the end of tax season. Some stories were major market movers, while others you may have missed.

Click ahead to see what we believe are the more significant business events of the past week.

By Allen Wastler
Posted 20 April 2012

What do you do in an election year to counter rising gas prices? Well, the Obama administration announced a plan to rein in oil speculation,which mostly amounted to increasing the staff and improving the technology used by the government to monitor the market. That actually got some supportive comments in the industry, although there were some predictable political potshots.

But provisions to increase margin requirements for oil traders has some thinkingthe market could get even MORE volatile.

“In the case of crude oil, the prices paid in the market reflect underlying conditions that range from basic supply and demand to geopolitical threats and monetary policy, just to name a few,” John Kilduff, an oil expert and CNBC contributor, wrote in a guest blog for us.“So, to paraphrase, the fault of the high gasoline prices lies not with the speculators, but with ourselves.“

Following news of strong corporate earnings reports and as worries about Europe eased, U.S. stocks rallied Tuesday with the Dow Jones industrial average adding over a 194 points to push the blue chip index back above 13,000.

Legendary investor Warren Buffett announced Tuesday that he has been diagnosed with Stage 1 prostate cancer.

"The good news is that I've been told by my doctors that my condition is not remotely life-threatening or even debilitating in any meaningful way," he said in a letter to shareholders. "I received my diagnosis last Wednesday. I then had a CAT scan and a bone scan on Thursday, followed by an MRI today. These tests showed no incidence of cancer elsewhere in my body." (Click here to read the full letter)

While the investing world seemed calmed by Buffett’s assurances (indeed, there were comparisons to his openness versus that of Steve Jobs), the announcement once again raised questions about who would succeed him as head of his investment company, Berkshire Hathaway. Who are the candidates? Pictured (L-R): Greg Abel, Ajit Jain, Tony Nicely, Matthew Rose, James Hambrick. For more on them click here.

And here's more on Buffett:

Doug Kass: Rethinking Berkshire

Whitney Tilson: No Reason to Sell

OK, maybe not the most earth-shaking development to the business world at large, but for those of us who enjoy an oaky Chardonnay or luscious Syrah, the news that a looming grape shortage in California will hit wine inventories this year is just plain sour.

“This year, with the slightly small harvest, we have moved past being balanced into a position that’s trending to shortage overall,” Silicon Valley Bank said in a report on the wine industry’s prospects.“High-end Cabernet and Zinfandel are clearly short and the only varietals we view as being close to balanced are the usual suspects in Merlot and Syrah.”

It will be good news for Oregon, Washington state and overseas producers, the bank suggested. Consumers? Maybe time to revisit some more hoppy offerings.

April 17 was the day of reckoning this year, thanks to a Sunday bump and a Monday holiday in Washington, D.C.

And with the annual day of pain came the predictable stories of tax protests and giveaways.

But the most popular story among our readers was word that more and because of the tax burden. 

"If it was just me then it would be one thing," says one man who did so. He’s a part-time investor who worried that having to share information with the IRS would deter future business partners — and upset his wife, who is Canadian. "Disclosing joint accounts I hold with my wife and anyone I ever want to do business with — that's just too much. My wife's account is none of their business."

Earnings season was in full force, with a slew of banks and techs and everything in between weighing in. (Check CNBC's Earnings Central for specific results)

The news looks pretty good, with about three-quarters of the companies reporting so far beating estimates. But some are questioning whether it’s really a sign of economic improvement or just an example of how well Corporate America has become at managing Wall Street expectations. Actual earnings do seem to be on the rise though, with results on track to beat last quarter by about 6 percent.

Problem is, even with some blowout results, the market seems preoccupied with other things. Read more here.

Pimco’s Mohamed El-Erian basically predictedthis kind of tug-of-war behavior between earnings and geopolitical events.

Spain keeps saying it’s not going to need a European bailout to help its banks and economy. The market apparently thinks otherwise. Debt auctions this past week saw yields for Spanish bonds rise sharply. Sure, the debt got sold, but on terms that signal the markets are pricing in bad times for the country.

"We will need no money from the rescue funds to refinance the banks," Spain’s economy minister told a newspaper.

Such assurances don’t seem to be winning over believers, though. IMF Chief Christine Lagarde, who is trying to raise money for an emergency bailout fund, suggested that European Union policymakers may have to sidestep troubled governments and start channeling bailout money directly into banks.

The Spanish market is down 17 percent over the past five weeks, marking its worst five-week losing streak since Sept. 19, 1998, when it dropped 23.1 percent over a five-week span.

Pictured left: The IBEX-35 index fell below 7,000 points for the first time in three years after the country had to pay higher rates in a 10-year bond auction.

Argentina hasn’t been a real hospitable place for investment in the recent decade. And now we can add another reason. The government moved to take over YPF, the Argentina-based unit of Spain’s Repsol energy conglomerate. Repsol is, of course, spluttering and angry, and there’s talk of going to various world forums for resolution,but most thing such moves will not amount to much.

Since its default in 2001, Argentina has pretty much thumbed its nose at the international business community, ignoring world trade rules and refusing to pay international judgments. (Is Argentina becoming the New Venezuela?)

And you can probably expect more restlessness there. Recent reports that there may be oil deposits around the Falkland Islands have already led to some déjà vu in Argentine-British relations.

Pictured left: View at sunset of the port next to the gas plant of the company YPF in Dock Sud, Buenos Aires, on April 19, 2012.

Of course, there were other newsy events during the week that drew some attention, albeit not straight market attention.

Like the tornadoes in the Midwest, the GSA party hearings, the Secret Service hooker scandal, India launching a long range rocket (successfully … North Korea should take note), fracking curbs. And yes, Dick Clark gave his final signoff salute.