To watch soccer highlights, for example, one analyst said he translated the names of the teams through Google and looked for them on Rutube, YouTube's Russian equivalent.
"It's draconian," the analyst said of his company's Web site blocks. "It's a job where you spend a lot of time waiting to get assignments back from superiors, and you have to find ways to kill the time."
"YouTube is the biggest obstacle," agreed an analyst at Bank of America Merrill Lynch who also spoke anonymously. He says that, instead, he searches Vimeo for videos, but it is not nearly as satisfying.
Steven Neil Kaplan, a professor of business and entrepreneurship at the University of Chicago Booth School of Business, said killing time had always been part of the job of a young analyst. While working as an analyst at Kidder Peabody in the early 1980s, he, too, would spend hours talking to his friends on the phone.
"You work very long hours," Mr. Kaplan said, "and often you're waiting for someone to turn something around."
Time spent slacking is acceptable as long as an analyst completes the material when it is assigned. "At the end of the day, if they don't get their work done, they're toast," he said.
Investment banks say regulation is the primary motivator for blocking social media. According to the Financial Industry Regulatory Authority, firms must keep a record of any business communication for three years. The rule applies to correspondence on any device or Web site. While firms are able to monitor e-mails and instant messages internally, it is impossible to track what one employee among hundreds of thousands is communicating on Twitter or through a Facebook chat.
"You have to be able to monitor what people are saying in real time," said a Goldman Sachs spokesman, Richard Siewert Jr.
Still, bans on YouTube and other streaming content sites suggest the firewalls are also intended to stifle distractions in the workplace. While banks are wary of media sharing sites because of their comments sections, they say it is also a bandwidth issue; 200,000 employees streaming YouTube videos hinders their software systems.
"It's about the culture," said the JPMorgan analyst. "We're not a start-up. It's a buttoned-up workplace."
To access blocked content and stay connected, he said he connected to JPMorgan's guest Wi-Fi using his iPhone or iPad. "It's nice to be able to have touch points to connect with your life, whether that's checking your Gmail or Facebook to see whose birthday it is."
Personal mobile devices are a prime workaround, and Mr. Siewert said even many senior executives used them throughout the day. "Even Bloomberg TV is hard to watch on our computers," he said. "In the office, you'll often find people gathered around an iPad watching something on CNBC or Bloomberg they didn't see in real time."
But analysts say streaming video on phones and tablets is clunky and does not fill the void generated by the Internet blocks.
The ability to access media, both for social and personal entertainment purposes, varies by bank and group. At Credit Suisse and Deutsche Bank, social networks are blocked but not media sharing sites. The occasional crowding around a desk for a funny YouTube video can offer solace during the grind of a long day. Still, some formalities apply.
"I'll plug in music usually around 5 or 6 in the afternoon, when my bosses start to go home and the environment becomes more relaxed," said one Credit Suisse analyst. Unable to access Spotify or Pandora, analysts said they streamed music through Web start-ups like SoundCloud and Grooveshark.
According to the research firm Gartner, the number of global organizations blocking social media is declining 10 percent annually. By 2014, fewer than 30 percent of all large organizations are expected to be blocking employee access to social media. As other traditionally strait-laced industries like consulting and law increasingly incorporate social media in the workplace, the financial services are lagging.
"They have such tight regulations, and the fines and the consequences are so extreme, that it's easier to understand why they are taking this approach," said Brian Platz, chief operating officer for the human resources technology firm SilkRoad. "The bigger problem they have is, whatever approach they're taking isn't preventing it anyway."
Bank of America Merrill Lynch, Barclays and JPMorgan declined to comment for this article.
Goldman Sachs, however, is working with the software company Hearsay Social to make social media platforms more accessible. Last month, Goldman started making its Twitter feed available to employees through the company's intranet.
"You don't want to be so restrictive that people are conducting activity on their nonwork computers because that's not allowed," Mr. Siewert said. "So we have to make the system inside our walls as modern as possible while staying within the rules. The impediment at institutions like ours is often technology or lawyers, and in both cases, I found that wasn't really true here. It was just culture."
For the young analyst at Bank of America, he has replaced Web entertainment with a quick walk outside.
"My bosses say it's healthier," he said. "At the same time, I just want to laugh. Watching a video is one of those things you can share with the guy in the cube next to you and relax during some downtime."