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 it faced allegations of securities fraud and insider trading and an eventual 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 Broadcom Corporation (NASDAQ: BRCM), Dynavax Technologies Corporation (DVAX 2.75%), and Hercules Offshore (HERO.DL).

Broadcom Corporation is a telecom chipmaker whose stock has averaged 1.4% annual growth over the past decade, dropping about 15% over the past year. It's introducing some new cellular products that it hopes will gain wide acceptance in 2015. If it does, its stock should perform well. If not, it may be "lights out" for the company, per my colleague Ashraf Eassa. Bulls are hopeful about its investments in the infrastructure, mobile, and wearable-computing arena, while bears don't like the company's deteriorating financials and disappointing recent quarterly results. Broadcom's stock yields 1.6%.

Dynavax Technologies, with a market capitalization near $360 million, has fallen by almost 50% over the past year. It's a vaccine specialist, with a lot of hope pinned on its adult hepatitis B vaccine Heplisav, which has experienced some bumps in the approval process and is currently in some late-stage trials. Bulls point out that the company has other promising drugs in its pipeline and think its stock has been overly punished. In its latest quarter, it posted narrower losses than in the year-ago quarter and revenue up 68%.

Hercules Offshore is a shallow-water drilling specialist, serving the oil and gas industry. Its stock is down some 37% over the past year, but its last quarter was very encouraging, with revenue jumping 38% over year-ago levels, in part due to four new international rigs. That revenue was still a bit below expectations, and income from continuing operations dropped. Still, there was ample good news, such as rising dayrates and management's expectations of stabilizing pricing. Hercules is also signing new contracts, such as one worth about $420 million, to provide drilling services for Maersk Oil North Sea UK Limited for five years.