if stock is going down a lot in one month what option should I purchase

 If a stock is dropping significantly over a one-month period, the primary option to purchase to profit from this downward move is a Long Put Option. A long put gives you the right to sell the stock at a set price (strike price), allowing you to profit as the share price falls below that level. 

Here are the specific options strategies for a rapidly falling stock, ranked by risk and objective:

1. Long Put Option (Bearish Speculation)

• What it is: Buying a put option (usually At-the-Money or slightly Out-of-the-Money) with an expiration date at least one month out to allow time for the drop to continue.
• Best for: When you have high conviction that the stock will continue to fall rapidly.
• Risk/Reward: Risk is limited strictly to the premium (price) paid for the option, while profit potential is high if the stock crashes.
• Tip: Buying puts on a stock that has already dropped a lot may be expensive due to high implied volatility. 

2. Bear Put Spread (Lower Cost, Controlled Risk) 

• What it is: A "vertical spread" where you buy a put option at a higher strike price and simultaneously sell a put option at a lower strike price (same expiration).
• Best for: When you are bearish but want to lower the cost of the trade and reduce the impact of high volatility.
• Risk/Reward: The potential profit is capped, but the risk is also lower than buying a straight put because the premium collected from the sold put offsets the cost of the bought put. 

3. Married Put (Hedging)

• What it is: If you already own 100+ shares of the stock and want to protect your position while still participating in a potential (but unlikely) rebound, you buy a put option.
• Best for: Protecting against further massive losses on a stock you own, acting as an "insurance policy". 

Key Considerations for a 1-Month Drop

• Implied Volatility (IV): When a stock is dropping fast, options premiums become very high (high IV). Buying puts can be expensive, and if the stock stabilizes, the "IV crush" can make your put lose value even if the stock price doesn't rise.
• Time Decay (Theta): Options have expiration dates. If the stock takes two months to drop, a 1-month put will expire worthless.
• Strike Selection: If you believe a fast drop is coming, buying At-the-Money (ATM) puts is usually preferred for the best balance of leverage and probability. 

Disclaimer: Options trading involves high risk and is not suitable for all investors. The information provided here is for educational purposes only and does not constitute financial advice.