A difference between this kind of credit operation on one hand and commercial credit on the other may be found in the fact that whereas reimbursement or liquidation of commercial credit comes from the interchange of existing goods or goods which are on the point of being rendered consumable, investment credit may eventually be liquidated as a result of savings made through the increase of productive power. Both interest and principal will be repaid to those who have advanced the current funds only as a result of a real increase in wealth resulting from the productive operation. It is evident from this analysis that the operations which are covered by the term investment banking rest upon a very different basis from that which is usually included under the term commercial credit. The function of the investment bank or credit institution is that of accumulating units of savings or current funds whose owners are willing to allow them to be converted into investments - productive or income-yielding opportunities. The difference between such credit and that furnished by the commercial bank is ordinarily spoken of as being one of time, but, as has already been frequently indicated, the essential difference is not that of time, but rather of the use that is made of time. It is a difference in the character of the enterprise that is undertaken. The characteristic enterprise undertaken with the use of commercial credit is that of bringing together consumers and producers, while the characteristic enterprise undertaken by the investment institution is that of bringing together producers and those who desire income rather than immediate enjoyment of capital. This is a difference which, as will be seen, involves broad and fundamental differences of method in banking and far-reaching differences in canons of judgment as to banking soundness or liquidity.