By Jonathan Moreland, founder of and author of Profit From Legal Insider Trading.

NEW YORK ( TheStreet) -- Which insiders are selling and buying chunks of stocks?

Below are lists of the top 10 open-market insider purchases and sales filed at the Securities and Exchange Commission Thursday, April 21, 2011 as ranked by dollar value. Company executives and directors are in the best position to assess the attractiveness of their firms' shares, and here is how many of them are voting their wallets! 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.

Primerica (PRI) Citigroup DIR,BO 12,000,000 $260,715,600
Trimas (TRS) Heartland Industrial Assoc BO 4,500,000 $90,000,000
MSC Industrial Direct (MSM) Jacobson Mitchell DIR,BO 98,300 $6,983,775
Apollo (APOL) Sperling John G CB,DIR
100,000 $3,958,460
Prolor Biotech (PBTH) Stern Adam K DIR 479,271 $2,640,783
Mattel (MAT) Brothers Ellen L VP 38,000 $1,017,652
Kaiser Aluminum (KALU) Retirees Of Kaiser BO 19,879 $943,313
Global Power Equipment (GLPW) PPM America Capital BO 23,452 $653,186
Intermec (IN) Unitrin BO 52,272 $590,629
Hertz Global (HTZ) Baker Leighanne G VP 24,620 $418,540

Key to Titles:A=Assistant, AI=Affiliated Investor, AO=Accounting Officer, BD=Business Development, BO=Beneficial Owner, CAO=Chief Accounting Officer, CB=Chairman, CCO=Chief Compliance Officer, CEO=Chief Executive Officer, CFO=Chief Financial Officer, CIO=Chief Information Officer, CO=Compliance Officer, COO=Chief Operating Officer, CT=Controller, CTO=Chief Technology Officer, DIR=Director, EVP=Executive Vice President, F=Founder, FO=Financial Officer, GC=General Counsel, HR=Human Resources, IO=Information Officer, IR=Investor Relations, LO=Legal Officer, MD=Managing Director, O=Officer, OO=Operating Officer, PR=President, PT=Partner, REL=Relative of an insider, SEC=Secretary, SH=Shareholder, SO=Sales Officer, TO=Technology Officer, TR=Treasurer, TT=Trustee, VCB=Vice Chairman, VP=Vice President, X=Ex Officer or other title displayed.

Jonathan Moreland is the founder of, which produces a weekly newsletter and offers professional screening and alerting tools to analyze a proprietary, real-time insider data feed. He is also the principal of Insider Asset Management, a registered investment advisor in New York. Mr. Moreland has been analyzing insider data professionally for two decades and has been a contributor to since 2001. A fundamental analyst with an MBA in finance, Mr. Moreland long ago identified insider data as an excellent first screen to determine where to focus his research efforts. He is quoted frequently in the media for his insider analysis and stock recommendations stemming from it. He is also author of Profit From Legal Insider Trading.

Under no circumstances does the information in this column represent a recommendation to buy or sell stocks. While he cannot provide investment advice or recommendations, Moreland appreciates your feedback; click here to send him an email.