Pat steaks dry, then sprinkle with 3/4 teaspoon salt and 1/2 teaspoon pepper (total).
Heat 1 tablespoon oil in a 12-inch heavy skillet over high heat until it shimmers, then sauté steaks in 2 batches, turning once, about 8 minutes per batch for medium-rare. Transfer to a large plate and cover with foil.
Pour off fat from skillet, then sauté garlic in remaining tablespoon oil over medium-high heat until pale golden, about 30 seconds. Add wine and boil, stirring and scraping up brown bits, until reduced by half, 2 to 3 minutes. Add water, soy sauce, and any meat juices from plate and boil until reduced by half, 3 to 4 minutes.
Reduce heat to medium-low and whisk in butter, 1 piece at a time, until slightly thickened. Stir in parsley and pour sauce over steaks.