The income of the 400 wealthiest Americans swelled in 2006, soaring nearly 23 percent from the previous year, to an average of $263 million, according to data released Thursday by the Internal Revenue Service. Since 1996, this group has nearly doubled its share of all income earned in the United States. The top 400 paid just more than $18 billion in federal income taxes in 2006, or an average of $45 million, on a record $105 billion in total income – the lowest effective tax rate in the 15 years since the agency began releasing such data. That compares with nearly $1 trillion paid by all other individual taxpayers in 2006. The gains for the richest took place amid a booming economy, in which hedge funds and private equity firms blossomed and the subprime lending machine went into high gear. The rising wealth of the nation’s richest taxpayers will most likely intensify debate among tax and policy analysts about the equitability of the tax code, which analysts say favors the ultrawealthy. Tax cuts enacted by the Bush administration that benefit the wealthy are set to expire by 2011. ‘Until recently, we had a financial […]