In recent exchanges on Marx and MMT, one question has concerned the capacity of government spending to encourage private investment and promote employment. Some Marxists appear to regard MMT as incompatible with Marx on this question. My own view is that Marx and MMT are compatible, both in general and on this particular question, and that the contributions of both, when viewed together, hold an important long-term social implication. What follows is a set of remarks outlining my position. Remark 1 is intended to provide context and to identify what I regard as the main social implication following from a joint reading of Marx and MMT. Remark 2 notes the critical significance of Marx’s ‘law’ of the tendential fall in the profit rate when interpreting the long-term implications of MMT from a Marxist perspective. Remarks 3 to 10 concern private investment under capitalist conditions, its likely responsiveness to government spending, but also its crisis prone nature. Remark 11 questions the appropriateness of society pinning its future aspirations on private investment behavior. It is suggested that a transition to socialism is both preferable and, on the basis of MMT, already technically feasible for societies with their own currencies.