Reader's Digest ( RDA) is providing Wall Street with an abridged version of how not to do a corporate takeover. But these useful tips won't be found in a recent copy of the publishing company's pocket-sized magazine. Rather, they are disclosed in a recent regulatory filing chronicling Ripplewood Holding's proposed $1.6 billion buyout of Reader's Digest. The Pleasantville, N.Y. publisher reveals the private-equity firm twice offered to pay $18.50 a share for the company, almost 9% more than the $17 a share takeover price that Readers Digest's board ultimately agreed to in November. It appears Reader's Digest's fumbling of the lengthy negotiations with Ripplewood may have cost shareholders up to $150 million in a buyout premium. The lower takeout price also raises questions about the performance of Goldman Sachs ( GS), the company's investment bank, in trying to auction the company to the highest bidder. Officials with Reader's Digest and Goldman Sachs could not be reached for comment. Reader's Digest, in a regulatory filing late Friday, discloses that in March it received an unsolicited proposal from Ripplewood to buy the company for $18.50. At the time, Reader's Digest shares were selling for $14.40. But the company's board rejected the proposal and Ripplewood's request to enter into a period of exclusive negotiations aimed at ending in a leveraged buyout.