Snack maker Amplify and solar company Sunrun fall after IPOs; drug developer Zynerba rises

Shares of snack maker Amplify and residential solar company Sunrun both tumbled in their market debuts Wednesday. Shares of Zynerba Pharmaceuticals, a company developing drugs derived from cannabis compounds, rose in its initial public offering.

Shareholders of Amplify Snack Brands Inc., the maker of SkinnyPop ready-made popcorn and Paqui tortillas and tortilla chips, raised $270 million in the company's IPO. It shares were priced above expectations at $18 per share. All 15 million shares in the offering are being sold by company stockholders, so the Austin, Texas-based company won't get any of the proceeds.

The stock fell $1.62, or 9 percent, to $16.38 in afternoon trading. Shares are trading under the ticker symbol "BETR" on the New York Stock Exchange.

Residential solar company Sunrun Inc. sold 17.9 million shares for $14 per share, raising $250.6 million. The share price was at the midpoint of the San Francisco company's estimates.

Sunrun designs, installs, finances and insures solar panels on roofs, and reported around $199 million in revenue in 2014. Trading under the ticker symbol "RUN" on the Nasdaq exchange, the stock fell $2.89, or 20.6 percent, to $11.11 in afternoon trading.

Zynerba Pharmaceuticals Inc. is preparing to start human clinical trials of two drugs: a gel intended to treat conditions including epilepsy and osteoarthritis, and a patch designed to treat fibromyalgia and peripheral nerve pain. Its drugs are based on synthetic compounds derived from cannabis, and the company says they are intended to be absorbed through the skin.

The Devon, Pennsylvania-based company says the drugs might be absorbed into the body faster and more reliably and with lower dosage levels than cannabis drugs that are given orally. It won't immediately seek permission to study the gel drug in the U.S., saying early studies will be conducted in Australia.

Zynerba sold 3 million shares priced at $14 each, raising $42 million, the midpoint of the company's estimates. Its shares, trading under the ticker symbol "ZYNE" on the Nasdaq exchange, jumped $3.09, or 22.1 percent, to $17.09 in midday dealings.