Yahoo bid costs Gates $3.8 billion, Forbes richest man titleForbes magazine reports that, worth $58 billion, Bill Gates is no longer the world's richest man. He's the third-richest. Although more than half of his wealth is invested outside Microsoft, Gates can likely blame the bad news on his oldest buddy. Steve Ballmer's unsolicited bid for Yahoo tanked Gates's net worth. Between the day before Ballmer announced the bid and February 11, when Forbes finished its accounting, Microsoft shares fell 15 percent. (Photo by Esparta)