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 open-market insider purchases and sales filed at the Securities and Exchange Commission Wednesday, May 18, 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.

China Biotics (CHBT) Value Holdings Capital BO 400,000 $4,558,506
Kraton Performance Polymers (KRA) GMT Capital BO 56,400 $2,045,064
Getty Realty (GTY) Liebowitz Leo DIR 50,000 $1,224,149
Avnet (AVT) Lawrence James A DIR 28,000 $1,007,720
Reynolds American (RAI) Zillmer John J DIR 10,000 $387,452
Fifth Street Finance (FSC) Tannenbaum Leonard M CEO,DIR 30,000 $366,439
Cenveo (CVO) Burton Robert G Sr CB,CEO
40,000 $249,876
Weatherford International (WFT) Duroc Danner Bernard J CB,PR
10,000 $191,800
Vanguard Natural Resources (VNR) Robert Richard A VP,CFO 5,000 $137,450
Looksmart (LOOK) Kauffman Scott L DIR 50,000 $94,954
LyondellBasell Industries (LYB) Ares Corporate Opp Fund DIR 8,432,841 $324,917,376
Microsoft (MSFT) Gates William H DIR 5,000,000 $123,802,000
Clearwire (CLWR) Intel BO 2,860,000 $12,400,200
Mitek Systems (MITK) Harland Clarke BO 2,142,856 $11,999,994
F5 Networks (FFIV) McAdam John PR,CEO
50,000 $5,274,542
Validus (VR) Singh Alok DIR 121,900 $3,897,399
American Financial (AFG) Lindner S Craig CEO,PR
100,000 $3,514,990
Scotts Miracle (SMG) Hagedorn Partnership BO 54,101 $3,100,574
Inphi (IPHI) Banatao Diosdado P DIR 114,500 $2,264,591
Viking Systems (VKNG) Midsummer Investment BO 7,223,457 $1,805,864

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.