American Tower said it would merge with rival SpectraSite in a stock-for-stock exchange, creating the nation's largest tower company with more than 22,000 wireless and broadcast towers and more than $1 billion in annual revenue.

American Tower will issue about 181 million shares in the transaction, valued at $3.1 billion based on the stock's closing price of $17.21 on May 3. SpectraSite shareholders will receive 3.575 shares of American Tower common stock for each share of common stock they hold in SpectraSite, for an exchange ratio of $61.53 per share. After the merger, American Tower shareholders will own about 59% of the combined company, with SpectraSite shareholders owning 41%. American Tower also will assume about $750 in SpectraSite debt.

The companies expect the merger to close in the second half of this year. The transaction — which was unanimously approved by the boards of directors of both companies — is subject to shareholder and regulatory approvals. A spokesperson for American Tower declined to confirm or deny speculation that the combined company would operate under the American Tower name.