The reasons for today's decline in Bitcoin's price can be analyzed from multiple perspectives:

1. Market reaction after Trump's victory in the U.S. election: The news of Trump's election victory triggered concerns in the market about uncertainties in future trade policies, especially his decision to impose additional tariffs on imports from China, Mexico, and Canada. These measures could lead to a tense global economic environment, affecting investors' risk appetite and causing declines in prices of risk assets, including Bitcoin.

2. Monthly expiration of Bitcoin options: A large number of Bitcoin options contracts are set to expire, which usually leads to increased market volatility. In such cases, investors may choose to close their positions early or adjust their holdings to avoid potential risks, which could also be a factor contributing to the decline in Bitcoin's price.

3. Profit-taking: After Bitcoin's price attempted multiple times to break through the $100,000 mark but failed, some investors may choose to sell at this time to lock in profits, which increases selling pressure and leads to a price decline.

4. ETF outflows: If there are outflows from exchange-traded funds (ETFs) related to Bitcoin, it indicates a decrease in institutional investors' interest in cryptocurrencies, which similarly could negatively affect Bitcoin's price.

5. Macroeconomic factors: The upcoming U.S. core personal consumption expenditures (PCE) data is an important indicator for measuring inflation and may influence the Federal Reserve's monetary policy decisions. Market participants will closely monitor this data, as any signals regarding interest rate changes could impact the prices of assets like Bitcoin.

In summary, the decline in Bitcoin's price is the result of multiple factors acting together, including political, economic, and technical elements. It is noteworthy that, while Bitcoin's price may continue to fluctuate in the short term, its value in the long term is still influenced by various factors, including technological advancements, market demand, and policy environment. Investors should consider these factors comprehensively when making investment decisions.