SAP-FICO: Company Codes and the Chart of Accounts

Though you can have multiple Charts of Accounts in SAP, company codes are assigned to only one chart of accounts. This is done in configuration (SPRO) (T-code: OB62 – Assign Company Code -> Chart of Accounts).
T-Code for Chart of Accounts

• T-code: F.10 – Chart of Accounts
  Report of accounts in a chart of accounts. Lots of ways to limit your results, but can’t limit by Company Code! You will definitely want to limit by chart of accounts.
• T-code: OB62 – Assign Company Code -> Chart of Accounts
  
• T-code: OBY2 – Copy Company Code: G/L Accounts
  When creating a new Company Code, just assigning it to a chart of accounts in OB62 doesn’t automatically create those accounts for the new company code. I.e. you won’t be able to post any entries until you’ve created the accounts for the company code. OBY2 lets you copy all of the accounts that were created for another company code to your new one.
• GL Postings are assigned to only 1 company code
  You can do “cross-company code” postings (i.e. DR CoCde A and CR CoCde B), but SAP will automatically generate the off-setting entries within each company code so that their books stay in balance (debits = credits). There is config around Intra-company postings to determine where you want those offsets to go.
• T-code: FS00 – Edit G/L Account Centrally
  This is usually the preferred t-code for manually creating GL Accounts since it allows you to create both the chart of accounts piece and the company code pieces.
• In FS00, you may need to create an account for multiple company codes. This can be done by changing the CoCde and using the “Create with reference button” in FS00.
  
• T-code: FSS0 – Edit Accounts in Company Code
  FSS0 allows you to edit just the Company Code (CoCde) portion of the GL Account.
• T-code: FSP0 – Edit Account in Chart of Accounts
  FSP0 allows you to edit just the Chart of Accounts portion of the GL Account.
• T-code: CX16 - Consolidation Chart of Accounts – Hierarchy Display
  CX16 allows you to create/edit financial statement items (FS Items) and their hierarchy for the Consolidated Chart of Accounts used in the EC-CS consolidation system.
  

Credit to : http://www.whypad.com/posts/sap-fico-company-codes-and-the-chart-of-accounts/81/