FitzWalter Capital said on Monday that it was abandoning its pursuit of online auction operator Auction Technology Group plc after a series of approaches was rejected.
The investment firm said it was informed last Thursday that its latest approach at 400p a share was unanimously rejected. This followed 11 other approaches.
"In light of the board's rejection and refusal to facilitate access to due diligence, FitzWalter confirms that it does not intend to make an offer for ATG," it said.
Under UK takeover rules, FitzWalter - ATG's biggest shareholder - had until 1700 GMT on Monday to either announce a firm intention to make an offer or walk away.
At 0807 GMT, ATG shares were down 7% at 287p.