Nikkei falls 1 pct as yen, economy hit exporters

* Nikkei falls 1 pct, erasing day's earlier gains

* Report that GM, Chrysler mulling bankruptcy dampens mood

* Exporters hurt by firmer yen, global economic downturn

* Nippon Oil, Nippon Mining Holdings gain on merger talk (Adds comment, stocks, details)

By Aiko Hayashi

TOKYO, Dec 4 (Reuters) - The Nikkei average fell 1 percent on Thursday as profit concerns in the global economic downturn hit exporters such as Honda Motor Co (7267.T), with merger news from Nippon Oil Corp (5001.T) failing to provide support.

Investors were also spooked by a Bloomberg report that General Motors (GM.N) and Chrysler LLC are considering accepting a pre-arranged bankruptcy plan in exchange for a U.S. government bailout, market analysts said. [ID:nBNG385182]

A stronger yen and a fall in U.S. stock futures SPc1 helped push the Nikkei lower.

Panasonic Corp (6752.T) slid after the Nikkei business daily said the world's biggest maker of plasma TVs has raised its buyout offer for Sanyo Electric (6764.T) by 10 yen to 130 yen per share in the hope of closing a deal this week. [ID:nT263242]  Continued...