We propose a simplified approach to mean-variance portfolio problems by changingtheir parametrisation from trading strategies to final positions. This allows us to treat,under a very mild no-arbitrage-type assumption, a whole range of quadratic optimisationproblems by simple mathematical tools...

For an investor with constant absolute risk aversion and a long horizon, who trades in amarket with constant investment opportunities and small proportional transaction costs, weobtain explicitly the optimal investment policy, its implied welfare, liquidity premium, andtrading volume. We...