Since Yahoo transitioned over to Bing at the end of April, it sounds like many advertisers have experienced a real drop in their Bing conversion rates. This is probably because their ad groups have been automatically opted into the "All Bing and Yahoo! search networks and syndicated search partners" option under the network distribution tab. Under this setting, the traffic will be of much lower quality - Yahoo used to drive in high volumes of "junk" clicks from its content network and now these clicks are being pumped into Bing. These extra clicks cause an increase in daily spend - which I'm sure wouldn't be a problem if they were actually converting well!We recommend switching your network distribution to "Only Bing and Yahoo! websites" so that your campaigns only attract the higher quality clicks from people who are actively searching for your product through a Bing or Yahoo! search engine. These clicks are likely to be better qualified and should lead to higher conversion rates.If you find your Bing (or Google) account is costing you too much or if you'd like to find out about increasing your lead volume, please get in touch and we'll happily take a look.