As the number four wireless carrier, the situation is grim for T-Mobile USA. In this industry, size does matter in terms of network coverage and access to phone options. Plus, there is downward pressure on pricing, such as from prepaid operators like Leap (LEAP) and MetroPCS (PCS).

Now, it looks like shareholders are losing their patience with T-Mobile, which is actually owned by German giant Deutsche Telekom AG (DT).

Hear the word subprime and you'll likely find many scared investors. But when it comes to DriveTime Automotive, the company has found a way to make money from this market segment -- at least for used auto sales.

And now the company has filed to go public. The offering is for up to $200 million.

When it comes to snowplows and salt spreaders for light trucks, Douglas Dynamics has top-notch brands in the industry. They include Western, Fisher and Blizzard.

Now, Douglas has filed to go public. The estimated size of the offering is about $150 million.

The widely anticipated IPO for Tesla Motors is finally here. Based in Silicon Valley, the company designs and manufactures high-performance, fully electric cars. The investors include the co-founders of Google (GOOG), Larry Page and Sergey Brin, and the founder is Elon Musk, who helped create PayPal.

The company's first car, which came on the market in 2008, is the Tesla Roadster. It can go from zero to 60 MHP in 3.9 seconds -- without any tailpipe emissions. On a single charge, the car can also go 236 miles. However, the price tag comes to a hefty $109,000.

Roughly a third of all mobile users download ringtones and 40% change them on a frequent basis (according to a study from Ipsos MediaCT). More importantly, ringtones are a lucrative source of revenues for mobile carriers and content owners.

To keep up the innovation, the next phase in the market is actually video ringtones. And this is the focus of Vringo, which has filed to go public.

Back in late 2007, Motricity agreed to purchase the mobile division of InfoSpace (INSP) for $135 million in cash. It was a critical deal since it resulted in getting major customer contracts as well as a strong technology platform, called mCore.

Now comes the next part of the strategy: an IPO. The filing came late last week.

For a mega private equity firm like Blackstone (BX), there's a need to get liquidity on a mega scale. So this week, the firm prepared for one of its holdings, Travelport, to go public. The deal could be worth as much as $3 billion.

Blackstone will float the deal on the London Stock Exchange. There will also be the issuance of 7.2% of the stock to Government of Singapore Investment Corp. (for about $225 million).

A new book, The Prince of Silicon Valley, chronicles the dealmaking of the IPO king of the 1990s: Frank Quattrone. He made a fortune as he helped more than 100 tech companies go public, which included marquee names like Cisco (CSCO), Netscape and Amazon.com (AMZN).

But those days seem quaint. In fact, the tech IPO market has been a backwater for the past decade, even though there have been some big deals -- like the offerings of Google (GOOG) and Salesforce.com (CRM).

The history of DynaVox goes back to 1983, when the company was spun-off from Carnegie Mellon University. Over time, the company has built some key technologies in the voice market, with a focus on the disabled. DynaVox has also made a variety of acquisitions along the way.

Now, the company wants to get some liquidity and pay down debt. To this end, DynaVox has filed to go public.

The name of the company is fairly ordinary: IFM Investments Limited. Yet, it is the exclusive franchisor of the CENTURY 21 brand in China (since 2000).

And to capitalize on the growth, IFM has filed to go public. In fact, this is one of the first filings in 2010.

Look, 2009 was a "flush" year. Market rallies were constrained by the low baseline set at the end of 2008, unemployment was high and caution defined nearly every corporate decision. The travel market sucked. The art market sucked. The financial industry labored on with the support of taxpayer money while 140 banks were forced to call it quits. So, we turn to the new year, as yet undefined, for excitement of the type we want ... and it seems likely to deliver. As Nero played from the rooftops, the social media industry inched forward to the climax we hope to see this year -- the initial public offering.

The action hasn't really begun, and the signals emitted are open to various interpretations. Nonetheless, Facebook's new dual-class stock structure is hard to miss, as it would protect the influence of early entrants to the company -- either as investors or options-compensated employees in the event that the 350 million-strong social networking site brings ownership opportunities to the public.

While the IPO market was tough for 2009, the fact remains that it was still lucrative market for Wall Street. In fact, because of the fall of several venerable financial services firms -- as well as some mergers -- it was easier to snag juicy assignments.

Just how lucrative can IPOs be? Well, an investment bank will charge 5% to 6% of the amount raised. Yes, this can add up quickly.

When it comes to cleantech, a company usually needs cutting-edge technologies, key strategic partners, lots of money and patience. In fact, these factors may still be not enough. After all, it's incredibly difficult to get people and companies to change their ways.

Despite all this, there are a variety of companies trying to make cleantech work. Just look at Codexis. Speaking of money, the company filed for an IPO this week.

Lately, the market for local online advertising has heated up. Based on various reports, it looks like Google (GOOG) was ready to pay $550 million for Yelp, which is a leader in the space. But the deal fell to pieces -- probably because of a disagreement on the valuation.

This definitely bodes well for another player, ReachLocal. In fact, this week the company filed to go public.

While cleantech seems poised to be a huge growth opportunity, the fact is that IPO investors have been somewhat skeptical. Just last week, the thin film panel maker, Trony Solar Holdings, pulled its public offering.

But, this is not stopping other cleantech companies from trying. For example, Solyndra has filed for an IPO.