Transurban Group Ltd chairman David Ryan defended the company and its Board on its decision to turn down improved takeover offers from the Canada Pension Plan Investment Board (CPPIB), CP2 Ltd and Ontario Teachers' Pension Plan (OTPP).

Transurban's three largest shareholders, OTPPB , CPPIB, and Australian fund manager CP2 Ltd, offered $5.57 for each share but the Melbourne-based toll-road operator rejected the bid.

In a letter to shareholders, Transurban chairman David Ryan said the Board decided to reject both takeover proposals because "neither proposal offered sufficient value or certainty for the Board to recommend these proposals to security holders."

Ryan said that "the Transurban Group is in the best shape it has ever been." He stressed that the company's portfolio of toll road assets and pipeline of growth projects will contribute to Transurban's growth in earnings before interest, tax, depreciation and amortisation (EBITDA) and free cash flow over the next three to five years.

Transurban Group recently acquired the Lane Cove Tunnel in Sydney for $630.5 million and has undertaken a capital raising to raise $542.3 million at an offer price of $4.60 per share.

Last week, shares of Transurban Group went down after one of its key shareholder, Ontario Teachers Pension Plan Board (OTPPB), sold its 13 per cent stake in the company.

Transurban Group posted a loss of $24.58 million for the 12 months to June 30, 2009.