NEW YORK, Dec 21 (Reuters) - - Cotton futures settled slightly firmer Wednesday on speculative buying in range-bound trade as major investors apparently left for the Christmas and New Year holidays, analysts said.

The key March cotton futures added 0.04 cent to close at 86.84 cents per lb, dealing from 86.26 to 87.38 cents.

Volume traded Wednesday hit nearly 8,200 lots, nearly 60 percent under the 30-day norm, Thomson Reuters preliminary data showed.

'The market is not showing any vulnerability,' said Mike Stevens, an independent expert in Mandeville, Louisiana, adding fiber contractss have been 'remarkably steady.'

Some 5,000 of the over 8,000 lots traded were in the March contract, and some traders said it could indicate steady commercial interest in the spot month.

Overall though, the tone in the cotton market was subdued especially since many players are gone for the holidays.

Fund managers and large investors who could cause major moves in cotton futures have closed their books for 2012 and will not be back until after the New Year, analysts said.

'We have six sessions left for the year. No one is hanging around for that,' one explained.

Fundamentally, traders believe cotton will not be an investor darling going into 2012.

They point to weak demand caused by fears the debt and budget crisis in the EU and the United States would continue to deflate cotton demand.

Once China finishes replenishing state reserves, there will be no sizable buyer left in the market, dealers said.

Total volume traded Tuesday rose to 9,136 lots from Monday's tally of 5,056 lots which had marked the lowest level since late in 2008, ICE Futures U.S. data showed.

Open interest, an indicator of investor exposure, was slightly higher at 150,183 lots, from the previous session's 148,910 lots, exchange data showed.