By Jonathan Moreland, founder of Insider Insights 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 mainly open-market insider purchases and sales filed at the Securities and Exchange Commission Friday, May 20, 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.

Furiex Pharmaceuticals (FURX) Eshelman Fredric N DIR 490,198 $6,866,186
Fairpoint Communications (FRP) Angelo Gordon BO 500,000 $5,294,885
China Biotics (CHBT) Value Holdings Capital BO 179,800 $2,137,220
Rexahn Pharmaceuticals (RNN) Ahn Chang Ho CB,CEO
1,008,078 $1,320,582
China Biologic Products (CBPO) Warburg Pincus Private Equity BO 67,521 $972,178
ADPT (ADPT) Steel Partners II BO 300,300 $865,174
Micros Systems (MCRS) Niroomand Kaweh VP 15,500 $778,565
Hudson Highland (HHGP) Haley John J DIR 50,000 $249,530
Primus Telecommunications (PMUG) Singer Karen BO 14,700 $205,065
Valhi (VHI) Simmons Harold C CB,DIR
5,000 $200,000
Mercadolibre (MELI) Levy Anton J DIR 274,838 $24,269,954
Pricesmart (PSMT) Estate Of Sol Price BO 500,000 $21,500,000
Perrigo (PRGO) Arkin Moshe DIR 180,362 $15,594,888
Genesee And Wyoming (GWR) Hellmann John C CEO,PR
96,451 $5,598,715
Silicon Laboratories (SLAB) Cash Harvey B DIR 101,200 $4,549,501
Leucadia National (LUK) Cumming Ian M CB,DIR
100,000 $3,709,000
Ttm Technologies (TTMI) Chung Tai Keung CEO 200,000 $3,331,400
Carbo Ceramics (CRR) Morris William C DIR,BO 17,860 $2,722,429
Cypress Semiconductor (CY) Nazarian Dana VP 84,140 $1,859,494
Qlik Technologies (QLIK) Nachmanson Jonas CTO 50,000 $1,551,247

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.