Every quarter, many money managers have to disclose what they've bought and sold, via "13F" filings. Their latest moves can get you thinking about some stocks you might want to buy -- or sell.

Today let's look at Gabelli Funds, the mutual-fund and closed-end fund arm of GAMCO Investors and familiar to many because of Mario Gabelli, the well-known value investor. Indeed, the folks at Institutional Investor named him Money Manager of the Year in 2011, citing an average annual return of 16.3% for his GAMCO Investors since its inception in 1977. That's darn impressive.

The company's reportable stock portfolio totaled $18.8 billion in value as of Dec. 31.

Interesting developments
So what does Gabelli Funds' latest quarterly 13F filing tell us? Here are a few interesting details.

The biggest new holdings are ViroPharma Incorporated and CNH Industrial. Other new holdings of interest include Kodiak Oil & Gas Corporation (NYSE: KOG). Kodiak Oil & Gas is a top operator in the promising Bakken Shale region, and has been boosting its production aggressively, thanks to fracking and other methods. Some worry, though, about Bakken oil being more flammable, the threat of increased regulation, and Kodiak's rising debt level. Bears point out that a stronger Kodiak is now able to fund growth from cash flow, not debt.

Among holdings in which Gabelli Funds increased its stake were Vale (NYSE:VALE) and Qualcomm Incorporated (NASDAQ:QCOM). Brazilian mining giant Vale has been cutting costs aggressively, reducing its investments, and selling assets, while focusing its explorations in Peru, Canada, Australia, and Brazil, and concentrating on its most promising opportunities, such as iron. Analyst Carlos De Alba at Morgan Stanley recently upgraded Vale's stock, from Equal-Weight to Overweight, seeing its risk-reward trade-off as attractive, and the company poised to increase profit margins. With a forward P/E ratio near 7, the stock does seem tempting.

Qualcomm (NASDAQ:QCOM) is the leading mobile chipmaker, supplying iDevices and Android devices with chips and making a lot of money licensing its technology. Its efforts to profit from China seem likely to pay off, and it has been growing in the health-care and networking arenas as well. (It might face some fines in China, though, depending on government decisions.) Qualcomm's Snapdragon 805 chip impressed at the Consumer Electronics Show recently. The company has been hiking its dividend aggressively for a decade now, and its yield is at 1.9%.

Gabelli Funds reduced its stake in lots of companies, including Philip Morris International (NYSE:PM). Philip Morris has been challenged by many smokers quitting or switching to value brands, and by increased regulations and taxes. Bulls are pinning hope on emerging markets and its embrace of electronic cigarettes and heated products. Bears don't like its debt, though. The company's fourth quarter featured higher prices, lower shipment volumes, and negative effects from currency translations caused by a strong dollar. Philip Morris International yields 4.8% and its dividend looks rather secure, thanks to its sizable free cash flow.

Finally, Gabelli Funds' biggest closed positions included Dell and Onyx Pharmaceuticals. Other closed positions of interest include Globe Specialty Metals (NASDAQ:GSM). Globe Specialty Materials specializes in silicon metals and alloys. Its second quarter featured estimate-topping earnings, but revenue missed estimates by a bit. Management notes, "As the demand and pricing environment improves for many of our products, we continue to drive operational efficiencies and margins across the business through cost savings measures." Globe Specialty Materials has announced a stock buyback plan, valued at up to $75 million. Its stock yields 1.6%. The company has boosted its capacity by acquiring Siltech.

We should never blindly copy any investor's moves, no matter how talented the investor. But it can be useful to keep an eye on what smart folks are doing, and 13F forms can be great places to find intriguing candidates for our portfolios.