ZURICH, Oct 29 (Reuters) - The Swiss National Bank posted a loss of 2.075 billion francs during its third quarter, the central bank reported on Friday, as profits from its bond holdings and negative interest rates failed to cover losses from weaker equity markets. The SNB, which holds 23% of its 957 billion francs of foreign currency assets in stocks, reported a loss of 2.354 billion Swiss francs from its foreign currency positions in the three months to the end of Sept. The MSCI All Country World Price Index fell by 1.7% during the quarter, as concerns about supplier bottlenecks, energy supplies and inflation weighed on companies and markets. The SNB made a profit of 109.5 million Swiss francs from a valuation gain on its gold holdings, while it made a profit of 250 million francs from its Swiss franc positions, mainly the negative interest rates it charges commercial banks for parking money overnight. Reporting by John Revill and Riham Alkousaa; editing by Brenna Hughes Neghaiwi