The latest 13F season is here, when many money managers issue required reports on their holdings. It can be worthwhile to pay attention, as you might get an investment idea or two by seeing what some major investors have been buying and selling.

For example, consider Point72 Asset Management, formerly known as SAC Capital Advisors. SAC Capital, run by Steven Cohen, was one of the biggest hedge fund companies around -- until allegations of securities fraud and insider trading led to a hefty fine of more than $1 billion. Now the company, which will no longer manage anyone's money other than that of Cohen, his family, and some employees, has a new name. (It's worth noting that Cohen reportedly averaged returns of roughly 30% annually over two decades.)

The company's latest 13F report shows that it reduced or eliminated positions in Forest Oil Corporation (NYSE: FST), Nokia Corporation (NOK 2.03%), and Orexigen Therapeutics (NASDAQ: OREX).

Forest Oil Corporation is a small company with a market cap near $260 million. It hasn't always been so small, though: Its stock is down more than 50% over the past year. Ouch. Almost 100 years old, Forest Oil is a North-America-focused oil and gas company, and it recently announced plans to be acquired by privately held Sabine Oil and Gas. Disappointing drilling results had left Forest Oil deep in debt, so the combination is welcome news.

Finland-based Nokia Corporation, once a telecom equipment powerhouse, is working on turning itself around. Nokia has sold its handset business to Microsoft for about $7 billion, and among other initiatives, it's moving into the connected-car arena, aiming for a piece of the Internet of Things pie. The cash from the big sale will go a long way to paying down debt and may result in dividends and share buybacks, as well. Fool analysts like Nokia's shift from devices toward networking, as it's likely to be more profitable. But some don't see sufficient growth, and wonder about the sustainability of proposed dividends. Nokia's first quarter featured revenue was down 15% year-over-year, but some divisions were doing well -- its HERE mapping business saw 13% growth in external sales, for example.

Orexigen Therapeutics is a biotech company focused on fighting obesity. Bulls hope that its Contrave drug will win FDA approval very soon -- though if it does, it will face competing products already on the market, even if those formulas are not exactly selling like hotcakes so far. Contrave may have an advantage in that it has undergone more extensive testing. Meanwhile, though, Orexigen's first quarter featured wider-than-expected losses. Management has pointed out that the drug might be of particular use for those with both obesity and diabetes.