In a victory for common sense, the trading behavior of company executives, directors, and large shareholders in the stocks of firms they're registered "insiders" at have been proven profitable to monitor by both academic studies and (more importantly) the experience of your fellow professional investors.

Below are lists of the top 10 mainly open-market insider purchases and sales filed at the Securities and Exchange Commission Friday, January 25, 2013 as ranked by dollar value.

Please note, however, that these are factual lists, not buy and sell recommendations. Dollar value is only one metric to assess the importance of an insider transaction, and, frankly, often not even the most important metric that determines if an insider transaction is significant.

In purchases, the private investment firm BVF Partners, a beneficial owner of biotechnology company Ligand Pharmaceuticals (NASDAQ:LGND), bought $783,181 worth of company stock. David Yost, a Director of Bank of America (NYSE:BAC) since August 2012, bought $230,600 worth of company stock. At bank holding company Kentucky Bancshares (PINK:KTYB), Director Buckner Woodford IV bought $43,480 worth of company stock. Additionally, Vice President James Elliott bought $19,750, and President and CEO Louis Prichard bought $14,283 worth of company stock. Wendy Beck, Vice President and Chief Financial Officer of Norwegian Cruise Line (NASDAQ:NCLH), bought $22,800 worth of company stock.

In sales, the MasterCard Foundation, a private, independent foundation devoted to microfinance in developing countries, as well as beneficiary owner of MasterCard (NYSE:MA), sold $18,493,454 worth of company stock. Sanderling Ventures Partners, an investment firm dedicated to building new biomedical companies and beneficial owner of Pacira Pharmaceuticals (NASDAQ:PCRX), sold $9,465,000 worth of company stock. The money management firm Adage Capital, a beneficial owner of Boulder Brands (NASDAQ:BDBD), sold $2,985,435 worth of company stock. The company, formerly known as Smart Balance before it officially changed its name earlier this month, is the fourth largest marketer of natural foods. At IBM (NYSE:IBM), Vice President  Robert Weber sold $1,473,460 worth of company stock. 

At InsiderInsights.com, we find new investment ideas just about every day using these and more intricate insider screens to determine where we should focus our subsequent fundamental and technical analysis. And while stocks don't (or shouldn't) move up or down based on insider activity alone, insiders tend to be good indicators of when real stock-moving events like earnings surprises, corporate actions, and new products may be in the offing.

Insider Purchases

#:	Filer Name	Insider Titles	Company Name	Ticker	Trans Type	Dollar Value
1	Bvf Partners	BO	Ligand Pharm	LGND	B	$783,181
2	Yost R David	DIR	Bank Of America	BAC	B	$230,600
3	Cannell Capital	BO	Multiband	MBND	B	$102,345
4	Maggiore Christopher	BO	Health Enhancement	HEPI	B	$51,396
5	Woodford Buckner Iv	DIR	Kentucky Bancshares	KTYB	B	$43,480
6	Buck William G	DIR	Cardinal Financial	CFNL	B	$24,480
7	Beck Wendy A	VP,CFO	Norwegian Cruise Line	NCLH	JB*	$22,800
8	Elliott James L	VP	Kentucky Bancshares	KTYB	B	$19,750
9	Prichard Louis	PR,CEO,DIR	Kentucky Bancshares	KTYB	B	$14,283
10	Williams Tryon M	CB,DIR,BO	Bingo Com	BNGOF	B	$10,000

Source: InsiderInsights.com | Key to Insider Title and Trans Type Codes

Insider Sales

#:	Filer Name	Insider Titles	Company Name	Ticker	Trans Type	Dollar Value
1	Mastercard Fdn	BO	Mastercard	MA	S	$18,493,454
2	Sanderling Vent Part	BO	Pacira Pharm	PCRX	JS*	$9,465,000
3	Adage Capital	BO	Boulder Brands	BDBD	S	$2,985,435
4	Hamlin Clay W	DIR	Corp Office Props	OFC	AS	$2,941,266
5	Addington Hills	BO	Ixia	XXIA	S	$2,524,145
6	Dixon Denmar J	VCB,VP,DIR	Walter Investment	WAC	AS	$2,368,634
7	Schulman Daniel	PR	American Express	AXP	S	$2,149,506
8	Hagedorn James	CB,CEO,BO	Scotts Miracle Gro	SMG	AS	$1,675,959
9	Weber Robert C	VP	IBM	IBM	S	$1,473,460
10	Klinck John L Jr	VP	State Street	STT	S	$1,208,244

Source: InsiderInsights.com | Key to Insider Title and Trans Type Codes

Editor's note: Jonathan Moreland is the founder of Insider Insights and author of "Profit From Legal Insider Trading."