Citigroup (C) appears to be making plans to acquire another US bank less than a month after walking away from Wachovia (WB).The name of the possible acquisition isn't known but insiders say it overlaps geographically with Citigorup's retail banking unit which is concentrated in the Northeast California and Texas the Wall Street Journal reports.Wells Fargo (WFC) is completing its purchase of Wachovia; any deal now completed by Citigroup may look like a ho-hum runner-up prize.But Citigroup like other major banks seeks to secure a deeper base of deposits in the US. Adding new deposits and extending the bank's reach ...