SEC filing reveals Motorola gained $10 more per share than Google's initial offer

Google ended up paying $10 per share more than it initially proposed for Motorola Mobility after negotiations between the two firms saw the price rise from $30 to $40.

The revelation comes after Motorola filed a statement with the Securities and Exchange Commission outlining the terms and history of the merger as Google looks to secure regulatory approval.

"On 1 August 2011, Google sent a letter to the Motorola Mobility board of directors proposing an acquisition of Motorola Mobility by Google for $30 in cash per share of Motorola Mobility common stock," the document reads.

Motorola rejected this offer, however, and demanded $43.50 per share. Google countered with an offer of $37, but Motorola said that an offer of $40.50 or higher was likely to be accepted.

Google upped its offer to $40 per share, which was accepted by Motorola on 14 August, and the deal was announced the next day to a stunned market.

The document also reveals that Google faces the prospect of paying Motorola $2.5bn if the merger fails to gain regulatory approval, while Motorola will pay $375m if it calls off the deal.

The Google-Motorola Mobility merger sent shockwaves through the mobile world, and analysts speculated that the move could push Android partners such as Samsung and HTC to Windows Phone.

The acquisition appears to be based more on Google's desire to enhance its portfolio of wireless and mobile patents to fend off growing legal challenges to Android.

Nevertheless, some have noted that Motorola's strong portfolio of patents has not stopped other companies taking on Motorola in court, notably Microsoft, which could have serious consequences for Google.