Boiler room scams typically involve high-pressure sales tactics to promote fraudulent or speculative investments, often targeting inexperienced investors. Common types of investments in these scams include penny stocks, exotic financial products, and unregistered securities.

1. Penny Stocks: These are low-priced, thinly traded stocks of small companies, often over-the-counter (OTC). Scammers inflate the stock price through false information, and then sell their shares at a profit, leaving investors with worthless stock.

2. Exotic Financial Products: These may include complex instruments like derivatives, foreign exchange (forex) schemes, or cryptocurrency investments. Scammers exploit the lack of understanding of these products to mislead investors.

3. Unregistered Securities: Fraudsters often sell shares in companies not registered with regulatory authorities, making it difficult for investors to verify their legitimacy. These may include fake startups or non-existent ventures.

4. Pump-and-Dump Schemes: Scammers artificially inflate the price of a stock through misleading statements, then sell their shares once the price peaks, causing it to crash.

5. High-Yield Investment Programs (HYIPs): These promise unrealistically high returns with little to no risk, often involving Ponzi schemes where returns are paid from new investors' funds.

Boiler room scams thrive on urgency and secrecy, pressuring victims to act quickly without due diligence. Investors should always verify the legitimacy of investments and avoid unsolicited offers.