The decline in bank share prices, in Australia and worldwide, may do more to mess with the schemes of any rival bidders for St George Bank than they do for the actual bid in the market from Westpac.And assuming another bank wants to crash the Westpac/St George party, which remains conjecture.Shares in Westpac have declined 16 per cent since their closing price on May 13, theday shares resumed trading after Westpac made the terms for its takeover bid for St George public. Westpac's shares closed yesterday at $21.60.With the bid at 1.31 Westpac shares for each St George share, the Westpac offer as of yesterday values each happy dragon share at $28.30.St George shares have fallen eleven per cent for the same period. St George shares still trade at a four per cent premium to the Westpac offer, closing yesterday at $29.54.The share price of National, viewed by some as a potential rival bidder, has crashed 19 per cent since the offer. ANZ has fallen 14 per cent, with Commonwealth,  currently Australia's largest bank, losing seven per cent.Shares in the investment banking and funds' manager Macquarie Group have declined a fifth.A longer time horizon has Westpac 31 per cent lower than twelve-month highs of $31.32, reached towards the end of 2007, with St George declining 23 per cent from its $38.50 peak.For the same period National has fallen 38 per cent, Australia and New Zealand are down 37 per cent, with Commonwealth losing 32 per cent, and Macquarie Group closed 45 per cent lower.The Macquarie dividend re-investment price of $50.95 (including 2.5 per cent discount) was announced yesterday,  and to highlight the poor share price in recent years, the price is lower than that used to work out the terms under the previous three final dividend reinvestment plans - $86.44 in 2007, $63.60 in 2006 and $51.27 in 2005.