You can designate Marketable Securities as a funding source (deficit account). The account is used, with unused internally generated funds, to repay debt early. Marketable Securities can accumulate excess funds, (cash surplus account). Set Marketable Securities to a Surplus and/or Deficit account by clicking in the Surplus and/or Deficit columns. Select the funding source and order of use in the Apply Cash Surplus to... and Fund Cash Deficit with... sections.