NEW YORK (TheStreet) -- Shares of Petrobras (PBR.A) fell 5.74% to $5.42 in afternoon trading Thursday amid falling oil prices and a host of problems tied to the Brazilian state-owned energy company's ongoing corruption scandal.

First, Brazil's Federal Audits Court, the TCU, announced Wednesday that it had chosen to investigate whether Petrobras board members mismanaged the company.

Also on Wednesday, Brazil's Comptroller-General Office added six more construction and engineering firms to its investigation into contractors that allegedly participated in corrupt dealings at the energy company. This brings the total number of firms under investigation to 24. The claims allege that the firms overpriced their contracts in a multibillion-dollar scheme that pushed bribes to Petrobras executives and Brazilian politicians.

Swiss authorities also said Wednesday that they had frozen hundreds of millions of dollars in assets linked to the ongoing and widening Petrobras corruption scandal. Furthermore, the authorities said they have discovered hundreds of accounts at Swiss banks used to funnel bribes as part of the alleged activity at the company.

Brazilian President Dilma Rousseff also announced Wednesday a package of anti-corruption measures after rallies across the country on Sunday called for impeachment. A poll Wednesday showed her approval rating dropped to a new low. 

"We have the duty and obligation to fight impunity and corruption," Rousseff said a nationally broadcast speech.

The measures she announced included the criminalization of slush funds used to finance election campaigns, the seizure of assets of people found guilty of corruption, and the requirement that government officials have no criminal records.

Finally, oil prices dropped Thursday after a rally Wednesday afternoon. WTI crude was down 1.93% to $43.80 at 3:04 p.m., while Brent crude was down 2.65% to $54.43, according to CNBC.

"I wish this little five dollar stock were less important than it is. But it carries the weight of the world on its shoulders because, as we wrote last week, this company owes about $170 billion in U.S. denominated debt, which means it has to take weak reals and buy strong dollars to pay it back," says Jim Cramer, Portfolio Manager of the Action Alerts PLUS charitable trust.

"If you were to ask me what's the most dangerous financial situation in the world, it's this one, which used to be ten times larger than it is," Cramer continues. "Put it on your screen. I have it right in the middle of mine. I sure wish its symbol would change. I like PBR the beer, not the stock!"

Insight from TheStreet's Research Team

Tim Melvin commented on Petrobras in a recent post on RealMoney.com. Here is what Melvin had to say about the stock:  

Before moving away from the Bain & Co. private equity report I want to share a few more investable observations I came away with after reading it this past weekend. Each year I have read the report I find it incredibly useful as a guide to opportunities in certain sectors and regions of the world, and this year is no different.

This year's report highlights Brazil and some of the opportunities that may be available in that troubled nation. I have held some Brazilian stocks for a couple of years now and it has been a bumpy, unpleasant journey so far. Over my holding period, we have gone from "this looks like maximum pessimism" to "maybe they will vote her out and jumpstart things" to "you have got to be kidding me." We have seen widespread corruption involving Petrobras, continued weakness in the economy and, just this weekend, protestors taking to the streets to demand the impeachment of the president the country just reelected. Brazil is a mess and it's not getting better anytime soon.

- Tim Melvin, 'Prospecting in 2 Troubled Economies' originally published 3/18/2015 on RealMoney.com.

Want more information like this from Tim Melvin BEFORE your stock moves? Learn more about RealMoney.com now.

TheStreet Ratings team rates PETROBRAS-PETROL BRASILEIRO as a Hold with a ratings score of C-. TheStreet Ratings Team has this to say about their recommendation:

"We rate PETROBRAS-PETROL BRASILEIRO (PBR.A) a HOLD. The primary factors that have impacted our rating are mixed - some indicating strength, some showing weaknesses, with little evidence to justify the expectation of either a positive or negative performance for this stock relative to most other stocks. The company's strengths can be seen in multiple areas, such as its revenue growth, largely solid financial position with reasonable debt levels by most measures and attractive valuation levels. However, as a counter to these strengths, we also find weaknesses including disappointing return on equity, weak operating cash flow and poor profit margins."

You can view the full analysis from the report here: PBR.A Ratings Report