I follow quite a lot of companies, so the usefulness of a watchlist to me cannot be overstated. Without my watchlist, I'd be unable to keep up with my favorite sectors and see what's really moving the market. Even worse, I'd be lost when the time came to choose which stock I'm buying or shorting next.

Today is Watchlist Wednesday, so I'm discussing three companies that have crossed my radar in the past week -- and at what point I may consider taking action on these calls with my own money. Keep in mind, these aren't concrete buy or sell recommendations, and I don't guarantee I'll take action on the companies being discussed. But I promise you can follow my real-life transactions through my profile, and that I, like everyone else here at The Motley Fool, will continue to hold the integrity of our disclosure policy in the highest regard.

Tower Group (NASDAQ:TWGP)
Halloween came early for shareholders of property and casualty insurer Tower Group after an absolutely frightening past two months. Over that time, Tower Group delayed its second-quarter filing after discovering the need to readjust its loss reserves. The two-month wait dealt investors a much worse-than-expected $365 million capital reserve charge, and a whopping $215 million goodwill writedown. What's left is a company with a lot of potential for both optimists and short-sellers.

The case for bears is pretty simple. With Tower Group's hands tied behind its back with the need to shore up its capital position, it was forced to turn to the reinsurance market, and cede some of its policy revenue in exchange for the capital safety of its remaining insurance lines, which include workers compensation and auto insurance. With ratings agency Fitch downgrading Tower's credit rating, its ability to underwrite new business could be in question.

However, there's another side to this story. With Tower's massive losses now out in the open, they can hopefully be put in the rearview mirror, and Tower can get back to what insurers do best: boosting premiums to cover their costs. Understandably, Tower is going to be working with a smaller profit potential following its reinsurance agreements, and it may find near-term underwriting tougher to come by, but I feel confident that the company can be profitable on an annual basis as early as next year. This is what led me to take a position in Tower Group recently in my own portfolio -- as well as its forward P/E of just eight.

I certainly don't expect the company to pay a dividend anytime soon, nor do I expect a rebound back to $25; however, I feel that, once Tower does report, this will be trading well below its book value, and could easily rebound 50% or more. I'm certainly a realist, and aware that the negatives could easily outweigh my long position; but it's a gamble I'm willing to take and, potentially, a reason you should add this stock to your Watchlist.

Global Brass and Copper Holdings (NYSE:BRSS)
If you've been looking for another way to play the copper market in the U.S., but have been constrained by only two or three primary choices, then let me introduce you to the recently IPO'ed Global Brass and Copper Holdings, which operates as a converter, fabricator, and processor of specialized copper in North America.

The case against owning copper processors is that their business is very much dependent on strong economic growth. Copper is used in everything from electronics to major construction, so any weakening of the U.S. or Canadian economy would bode poorly for Global Brass' demand. In addition, following its successful IPO, the company's largest shareholder, KPS Capital Partners, sold 5 million shares at $16.50. Anytime your largest shareholder dumps a significant portion of its holdings, it tends to raise an eyebrow or two.

Despite these concerns, copper prices have held up considerably better than either gold or silver recently. The fact that copper is more abundant than either gold or silver, and has more practical uses, is one reason why prices have been relatively range-bound -- and range-bound isn't necessarily a bad thing in a weak commodity environment.

Global Brass' second-quarter results also show a company that's clicking on all cylinders. Volume was up 7.5% during the quarter, as improved housing demand, and end-coin market usage, drove processing up nearly 10 million pounds. Barring a complete collapse in the housing industry or copper prices, I'd say Global Brass' forward P/E of seven looks mighty intriguing and worth a closer look.

Crown Castle International (NYSE:CCI)
Like all previous weeks, I haven't forgotten about my short-selling faithful, which is why I now turn your attention to cellular tower operator Crown Castle.

Crown Castle made headlines earlier this week when it announced that it would be leasing about 9,100 cell towers from AT&T (NYSE:T) and purchasing an additional 600 for $4.85 billion. The deal does make sense for both companies, as AT&T had been looking to raise cash for a $14 billion network infrastructure upgrade, and Crown Castle is looking for ways to maintain its leading position as the No. 1 wireless-tower owner in the U.S. With all major service providers looking to expand their 4G LTE coverage, wireless-tower operators are set to see some major cash flow in the coming years.

But, this isn't a perfect deal for investors. In order to fund the transaction, Crown Castle will be issuing 36 million new shares as well as 7.5 million preferred shares. That alone is a 12.3% increase to Crown Castle's outstanding share count, which acts as a dilutive factor to existing shareholders. However, it does beat the alternative, which is taking on more debt. As of its most-recent quarter, Crown Castle boasted close to $10.7 billion in net debt.

Although cellular-tower operators are difficult to value based on earnings, and are more of a cash-flow play, I can't help but compare American Tower's (NYSE:AMT) bottom line with Crown Castle's to determine that American Tower is the clear winner of the two. American Tower, which has assets diversified outside the U.S. as well, has a lower debt-to-equity ratio, a dividend yielding 1.4%, and a forward P/E of 31. It appears to be no match for Crown Castle's U.S.-centric portfolio of assets, with no dividend, and a forward P/E that's double that of American Tower. Between its high-debt levels and coming dilution, I'd contend that Crown Castle's run higher is nearly finished.

Foolish roundup
Is my bullishness or bearishness misplaced? Share your thoughts in the comment section below, and consider following my cue by using these links to add these companies to your free, personalized watchlist to keep up on the latest news with each company:

Fool contributor Sean Williams owns shares of Tower Group, but has no material interest in any other companies mentioned in this article. You can follow him on CAPS under the screen name TMFUltraLong, track every pick he makes under the screen name TrackUltraLong, and check him out on Twitter, where he goes by the handle @TMFUltraLong.

The Motley Fool owns shares of, and recommends American Tower. It also has the following options: short November 2013 $72 puts on American Tower. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.