The uncertain fate of the estate tax moved slightly closer to resolution on Thursday.

The US House of Representatives voted to permanently extend the estate tax, approving a measure that would lock in a top rate of 45 per cent on estates worth more than $3 million for individuals or $7 million for couples.

But the Senate has yet to vote on extending the estate tax, which is due to expire next year. And even though Senate Democratic leaders would like to bring a vote to the floor by the end of the year, they are currently preoccupied with health care legislation and also face resistance from conservative Democrats as well as Republicans.

If no action is taken, the estate tax would be eliminated for a year, but would return in 2011 in a much more progressive form, with a top rate of 55 per cent levied on estates worth more than $1 million.