If the Russian stock market continues falling for another several days, investors will face margin calls, VTB bank Deputy Chairman Georgy Moos said late on Tuesday. \"Several more days like we are seeing now and we will see margin calls,\" Moos said. A margin call is a broker\'s demand on an investor using margin to deposit additional money or securities so that the margin account is brought up to the minimum maintenance margin. The global markets crisis has wiped about $200 billion off the value of local stocks with leading bourses losing up to 6 percent on Tuesday alone. However, Moos believes that the 2008 crisis, when margin calls ruined many a company, has taught a lesson to Russian banks. \"We see very few such loans. The loan portfolio to collateral ratio allows the value of the collateral to fall 50-60 percent. Only then we\'ll see a margin call,\" he said.