The two main ways are **short selling the stock** and **buying a put option**.

**1. Short selling**

Your broker arranges for you to borrow shares. You sell them now, then buy them back later and return them.

For example:

- You short 100 shares at $50, receiving $5,000.
- Next week, the price falls to $40.
- You buy back 100 shares for $4,000 and return them.
- Your profit is **$1,000 before borrowing costs and trading fees**.

Short selling requires margin collateral, and borrowing charges reduce your profit. [SEC explanation of short selling](https://www.investor.gov/introduction-investing/investing-basics/how-stock-markets-work/stock-purchases-and-sales-long-and)

The major risk is that the stock rises. At $70, buying back those shares would cost $7,000—a $2,000 loss. **Potential losses are theoretically unlimited**, because the share price can keep rising. [SEC discussion of short-selling risks](https://www.investor.gov/introduction-investing/general-resources/news-alerts/alerts-bulletins/leveraged-investing-strategies-know-risks-using-these-advanced-investment-tools)

**2. Buying a put option**

A put gives you the right to sell shares at a specified price—the *strike price*—by an expiration date. You pay an upfront price called the *premium*. You can sell the option itself to close your position. [SEC options guide](https://www.investor.gov/introduction-investing/general-resources/news-alerts/alerts-bulletins/investor-bulletins-63)

Hypothetically, with the stock at $50, you buy a $50-strike put for $2 per share. A standard U.S. stock option usually covers 100 shares, so it costs $200.

- If the stock is $40 at expiration, the put’s value is $1,000. Your profit is **$800 before fees**.
- If the stock is $49 at expiration, its value is $100. You **lose $100 despite correctly predicting a fall**.
- If the stock finishes at $50 or above, the put expires worthless and you lose the $200 premium.

For the purchased option itself, your maximum loss is the premium plus fees. Its price before expiration also depends on time remaining and expected volatility. [SEC options guide](https://www.investor.gov/introduction-investing/general-resources/news-alerts/alerts-bulletins/investor-bulletins-63)

For your “next week” scenario, **the size and timing of the fall matter**. A short sale needs the decline to cover your costs; a put needs favorable movement before expiration to overcome its purchase price. Brokerage access and trading requirements depend on your country and broker.