Russian companies with dollar-denominated listings in London plunged on Monday after the West moved to cut some Russian banks from the SWIFT messaging system. Sberbank SBER, -61.08% dropped 75%, and Lukoil LKOD, -52.41% fell 58%. Rosneft Oil ROSN, -42.56% dropped 41% as BP said it would exit its minority stake. Gazprom Neft GAZ, -23.95%, the oil producing subsidiary of Gazprom, dropped 25%, and PhosAgro PHOR, -66.23% skidded 55%.