In Switzerland, Foreign Exchange Reserves are the foreign assets held or controlled by the country central bank. The reserves are made of gold or a specific currency. They can also be special drawing rights and marketable securities denominated in foreign currencies like treasury bills, government bonds, corporate bonds and equities and foreign currency loans.
A higher than expected figure should be seen as positive (bullish) for the CHF while a lower than expected figure should be seen as negative (bearish) for the CHF.