SEC Filings

Home / Investors / Financials / SEC Filings
NASDAQ: CHKOTCPK: CHKAQ
YearTrailing 12-MonthsCalendar Year 2024Calendar Year 2023Calendar Year 2022Calendar Year 2021Calendar Year 2020Calendar Year 2019Calendar Year 2018Calendar Year 2017Calendar Year 2016Calendar Year 2015Calendar Year 2014Calendar Year 2013Calendar Year 2012Calendar Year 2011Calendar Year 2010Calendar Year 2009Calendar Year 2008Calendar Year 2007Calendar Year 2006Calendar Year 2005Calendar Year 2004Calendar Year 2003Calendar Year 2002Calendar Year 2001Calendar Year 2000Calendar Year 1999Calendar Year 1998Calendar Year 1997Calendar Year 1996Calendar Year 1995
ViewAll FilingsAnnual FilingsQuarterly FilingsCurrent FilingsRegistration StatementsSection 16Mergers & AcquisitionsProxy & Information StatementsOther
FormDescriptionDateFormat
424B3Form of prospectus reflecting facts events constituting substantive change from last formDec 9, 1998Open Form of prospectus reflecting facts events constituting substantive change from last form in HTML.Open Form of prospectus reflecting facts events constituting substantive change from last form in DOC file.Open Form of prospectus reflecting facts events constituting substantive change from last form in PDF file.Open Form of prospectus reflecting facts events constituting substantive change from last form in XLS file.
8-A12BRegistration of certain classes of securities 12(b) of the Securities Exchange ActNov 24, 1998Open Registration of certain classes of securities 12(b) of the Securities Exchange Act in HTML.Open Registration of certain classes of securities 12(b) of the Securities Exchange Act in DOC file.Open Registration of certain classes of securities 12(b) of the Securities Exchange Act in PDF file.Open Registration of certain classes of securities 12(b) of the Securities Exchange Act in XLS file.
424B3Form of prospectus reflecting facts events constituting substantive change from last formOct 6, 1998Open Form of prospectus reflecting facts events constituting substantive change from last form in HTML.Open Form of prospectus reflecting facts events constituting substantive change from last form in DOC file.Open Form of prospectus reflecting facts events constituting substantive change from last form in PDF file.Open Form of prospectus reflecting facts events constituting substantive change from last form in XLS file.
8-A12BRegistration of certain classes of securities 12(b) of the Securities Exchange ActSep 1, 1998Open Registration of certain classes of securities 12(b) of the Securities Exchange Act in HTML.Open Registration of certain classes of securities 12(b) of the Securities Exchange Act in DOC file.Open Registration of certain classes of securities 12(b) of the Securities Exchange Act in PDF file.Open Registration of certain classes of securities 12(b) of the Securities Exchange Act in XLS file.
424B3Form of prospectus reflecting facts events constituting substantive change from last formAug 27, 1998Open Form of prospectus reflecting facts events constituting substantive change from last form in HTML.Open Form of prospectus reflecting facts events constituting substantive change from last form in DOC file.Open Form of prospectus reflecting facts events constituting substantive change from last form in PDF file.Open Form of prospectus reflecting facts events constituting substantive change from last form in XLS file.
424B3Form of prospectus reflecting facts events constituting substantive change from last formAug 4, 1998Open Form of prospectus reflecting facts events constituting substantive change from last form in HTML.Open Form of prospectus reflecting facts events constituting substantive change from last form in DOC file.Open Form of prospectus reflecting facts events constituting substantive change from last form in PDF file.Open Form of prospectus reflecting facts events constituting substantive change from last form in XLS file.
424B3Form of prospectus reflecting facts events constituting substantive change from last formAug 4, 1998Open Form of prospectus reflecting facts events constituting substantive change from last form in HTML.Open Form of prospectus reflecting facts events constituting substantive change from last form in DOC file.Open Form of prospectus reflecting facts events constituting substantive change from last form in PDF file.Open Form of prospectus reflecting facts events constituting substantive change from last form in XLS file.
S-3/APre-effective amendment to an S-3 filingJul 29, 1998Open Pre-effective amendment to an S-3 filing in HTML.Open Pre-effective amendment to an S-3 filing in DOC file.Open Pre-effective amendment to an S-3 filing in PDF file.Open Pre-effective amendment to an S-3 filing in XLS file.
8-A12BRegistration of certain classes of securities 12(b) of the Securities Exchange ActJul 16, 1998Open Registration of certain classes of securities 12(b) of the Securities Exchange Act in HTML.Open Registration of certain classes of securities 12(b) of the Securities Exchange Act in DOC file.Open Registration of certain classes of securities 12(b) of the Securities Exchange Act in PDF file.Open Registration of certain classes of securities 12(b) of the Securities Exchange Act in XLS file.
S-3Simplified registration formJun 19, 1998Open Simplified registration form in HTML.Open Simplified registration form in DOC file.Open Simplified registration form in PDF file.Open Simplified registration form in XLS file.
S-4POS Post-effective amendment to an S-4EF filingJun 19, 1998Open POS Post-effective amendment to an S-4EF filing in HTML.Open POS Post-effective amendment to an S-4EF filing in DOC file.Open POS Post-effective amendment to an S-4EF filing in PDF file.Open POS Post-effective amendment to an S-4EF filing in XLS file.
424B3Form of prospectus reflecting facts events constituting substantive change from last formApr 30, 1998Open Form of prospectus reflecting facts events constituting substantive change from last form in HTML.Open Form of prospectus reflecting facts events constituting substantive change from last form in DOC file.Open Form of prospectus reflecting facts events constituting substantive change from last form in PDF file.Open Form of prospectus reflecting facts events constituting substantive change from last form in XLS file.
S-3Simplified registration formApr 21, 1998Open Simplified registration form in HTML.Open Simplified registration form in DOC file.Open Simplified registration form in PDF file.Open Simplified registration form in XLS file.
424B3Form of prospectus reflecting facts events constituting substantive change from last formApr 1, 1998Open Form of prospectus reflecting facts events constituting substantive change from last form in HTML.Open Form of prospectus reflecting facts events constituting substantive change from last form in DOC file.Open Form of prospectus reflecting facts events constituting substantive change from last form in PDF file.Open Form of prospectus reflecting facts events constituting substantive change from last form in XLS file.
S-4POS Post-effective amendment to an S-4EF filingMar 27, 1998Open POS Post-effective amendment to an S-4EF filing in HTML.Open POS Post-effective amendment to an S-4EF filing in DOC file.Open POS Post-effective amendment to an S-4EF filing in PDF file.Open POS Post-effective amendment to an S-4EF filing in XLS file.
POS AMPost-effective amendment to an S-Type filingMar 25, 1998Open Post-effective amendment to an S-Type filing in HTML.Open Post-effective amendment to an S-Type filing in DOC file.Open Post-effective amendment to an S-Type filing in PDF file.Open Post-effective amendment to an S-Type filing in XLS file.
S-8Securities offered to employees pursuant to employee benefit plansMar 25, 1998Open Securities offered to employees pursuant to employee benefit plans in HTML.Open Securities offered to employees pursuant to employee benefit plans in DOC file.Open Securities offered to employees pursuant to employee benefit plans in PDF file.Open Securities offered to employees pursuant to employee benefit plans in XLS file.
424B3Form of prospectus reflecting facts events constituting substantive change from last formFeb 17, 1998Open Form of prospectus reflecting facts events constituting substantive change from last form in HTML.Open Form of prospectus reflecting facts events constituting substantive change from last form in DOC file.Open Form of prospectus reflecting facts events constituting substantive change from last form in PDF file.Open Form of prospectus reflecting facts events constituting substantive change from last form in XLS file.
S-4POS Post-effective amendment to an S-4EF filingFeb 11, 1998Open POS Post-effective amendment to an S-4EF filing in HTML.Open POS Post-effective amendment to an S-4EF filing in DOC file.Open POS Post-effective amendment to an S-4EF filing in PDF file.Open POS Post-effective amendment to an S-4EF filing in XLS file.
Subscribe to Investor Email Alerts
* Required Fields
Scroll to Top