Scott Lubner, head of stock and stock derivatives strategy at Castle Securities, said that the US stock market will face volatility in the next two weeks due to the largest option expiration in history since June 19th, the end of quarter pension portfolio rebalancing, and investor position adjustments. Scott Lubner believes that the main theme of the US stock market in the second half of the year will still be upward, with current US households holding record levels of cash and retail investment behavior approaching institutional allocation.