Stocks making the biggest moves after hours: Cadence Design, Packaging Corp of America, SBA Communications and more

cnbc.com:

Check out the companies making headlines in extended trading.

Cadence Design Systems – Shares of computer software company gained 5% after hours following the company's quarterly earnings reports. Earnings and revenue for the first quarter both came in above consensus forecasts, according to FactSet. The company also issued upbeat full year earnings and revenue guidance.

Heidrick & Struggles – The executive search firm's shares fell more than 4% in extended trading, despite reporting an increase in profit and revenue for the first quarter. The company also recorded a slew of increased spending for consolidates salaries and benefits, cost of services and administrative expenses.

SBA Communications Corporation – Shares of the wireless communications company saw its stock rise 1.5% after reporting quarterly results, which included adjusted EBITDA that beat FactSet estimates and better-than-expected full year financial guidance. The company also announced it's repurchasing 1.3 million shares.

Packaging Corp of America – The packaging company's shares advanced 1.6% after company earnings. Adjusted EBITDA for the first quarter came in at $467.2 million, compared to FactSet estimates of $443.1 million.