Complex sentence: HFT uses proprietary trading strategies carried out by computers to move in and out of positions in seconds or fractions of a second, aiming to capture sometimes a fraction of a cent in profit on every trade.
Split into simpler sentences: HFT uses proprietary trading strategies carried out by computers to move in and out of positions in seconds or fractions of a second. High-frequency traders move in and out of short-term positions at high volumes aiming to capture sometimes a fraction of a cent in profit on every trade.