* Dollar tumbles as Trump beats earlier odds and pulls ahead
* Dollar/yen drops more than 3 pct, euro/dollar up more than 2 pct
* Mexico peso tanks to record low, Swiss franc jumps, loonie hit

The dollar tumbled more than three percent against the yen while the Mexican peso sank to a record low on Wednesday, as Republican Donald Trump took a shocking lead in the fiercely-contested US election.

The probability of a Trump win, which appeared inconceivable to many just a few months ago, put the markets into full risk-aversion mode, sending investors scurrying out of the dollar and into perceived safe-havens such as the Japanese yen and Swiss franc. The euro and sterling also rallied versus the greenback.
Trump scored a series of surprising wins in battleground states including Florida and Ohio, opening a path to the White House for the political outsider and rattling world markets counting on a win by Democrat Hillary Clinton.
The dollar slumped 3.8 percent to 101.210 yen in a volatile day that saw it rise to 105.480 earlier, when last-minute opinion polls put Clinton in favour.
The dollar fell 2.3 percent against the Swiss franc, another safe-haven, to 0.9552 franc. The euro rallied 2.5 percent to a two-month high of $1.1300.
"The catalyst behind the dollar's slide was reports that put Trump ahead of Clinton in the battleground state of Florida," said Junichi Ishikawa, senior forex strategist at IG Securities in Tokyo.
"Risk aversion is in the air with equities tumbling."
The Mexican peso, which has served as a barometer of the markets' expectations for a Trump presidency, handed back earlier gains and tumbled down versus the dollar. The peso weakened more than 13 percent to an all-time low of 20.75 pesos per dollar.
The scene was reminiscent of the turmoil that engulfed global financial markets after the June Brexit vote, when British voters opted to leave the European Union in a decision that wrongfooted investors and bookmakers.
"No one in the market expected the results that we're seeing so far," said Kaneo Ogino, director at foreign exchange research firm Global-info Co in Tokyo.
"Even if in the case there is a Clinton comeback and she wins, the market already has reacted to the point where the dollar would have trouble climbing back. It's mostly algo dealing in the market now, with dealers staying out. It's system trading, and it's hard for anyone to catch up."
The markets paid little heed as Japan's top currency diplomat signalled Tokyo's readiness to intervene in currencies as the yen soared.
"(Currency) moves are quite rough," Masatsugu Asakawa, vice finance minister for international affairs, told reporters, adding that he was watching markets with a "sense of urgency."
Trump has pledged to renegotiate the North American Free Trade Agreement (NAFTA) with Mexico and Canada, a move that could damage the economies of the export-heavy US neighbours.
The Canadian dollar fell to an eight-month low of C$1.3525 per dollar.
Investor anxiety has deepened in recent weeks on the prospect of a Trump victory as the controversial businessman, an anti-establishment political novice, is seen as a risk to global growth as he has pledged to renegotiate trade deals, impose high import tariffs and stirred fears of a currency war with China.
The Republican candidate has also stoked uncertainty over his stance in foreign policy and immigration, while Clinton is seen by markets as a known entity and likely to ensure political and financial stability.