Mexico peso sinks to 1-month low on downgrade bets

* Peso hits one-month low, hurt by downgrade worries

* Mexican currency declines 1.6 percent this week

* Stocks gain as U.S. unemployment seen nearing ceiling (Adds closing stock prices, debt movement)

MEXICO CITY, Nov 6 (Reuters) - Mexico's peso sank to a one-month low on Friday, hurt by concerns tax reforms passed last weekend will not be enough to stave off a downgrade of the country's debt.

The peso MXN=MEX01 lost 0.97 percent to 13.415 per U.S. dollar, closing out its worst week in a month and a half with around a 1.6 percent loss.

The IPC stock index .MXX closed up 0.45 percent to 29,868.62 after U.S. employment figures offered a few glimmers of hope for Mexico's top trading partner. The IPC gained 4.3 percent this week.

Last weekend, Mexican lawmakers finalized a watered-down version of President Felipe Calderon's fiscal reform package, which aims to raise taxes and help reduce Mexico's dependence on its waning oil industry.

Many analysts say the reforms are not deep enough to satisfy Wall Street ratings agencies that threaten to downgrade Mexico's debt unless the government widens its tax base.

"The interpretation is that the revenue law could result in a downgrade, and foreigners are deciding to put their money elsewhere while the uncertainty continues," said Juan Jose Resendiz, an analyst at Arka brokerage firm in Mexico City.