Vodafone’s shares fell on Wednesday after Verizon Communications ruled out a full takeover of the British based firm.
The US telecommunications giant said it does not “currently have any intention” to merge with or buy its partner.
Vodafone’s stock has risen more than 25 percent this year on hopes that it would sell its 45 percent stake in US mobile provider Verizon Wireless.
Fresh rumours sparked a big share price jump on Tuesday.
Vodafone and Verizon are struggling to agree a price that suits both. They have had an often fractious relationship in that joint venture, which was formed by the two groups in 1999.
Verizon’s statement followed a Financial Times report that cited unnamed sources as saying Verizon and its biggest US rival, AT&T, were working together on a joint bid.
The report said that, under the plan, Verizon would take Vodafone’s US assets and AT&T would have the rest.