NEW YORK (AP) — October often makes investors nervous, since that’s when some of the biggest crashes in stock market history happened. But this October, the market seemed unstoppable. The Standard & Poor’s 500 index closed at a record high seven times. The market climbed even after October began with the 16-day government shutdown and the threat of a potentially calamitous U.S. default. After being rattled by a series of down-to-the-wire budget battles in recent years, investors have become inured to the ways of Washington lawmakers. Instead of selling stocks, they kept their focus on what they say really matters: the Federal Reserve. The central bank is buying $85 billion of bonds every month to promote economic growth.