North Sea Brent crude fell 0.8% to $US99.97 a barrel - its first time below $US100 in more than 14 months - while gold dropped 1.2% to $US1252.
Britain's top shares dropped further from a recent 14-year high as companies with strong business ties to Scotland fell across the board.
Craigs Investment Partners broker Peter McIntyre said the weekend poll had ''spooked investors'', which prompted the European stock markets to pull back after four straight weekly gains.
''The pound got creamed, touching an intra-day low of $US1.6103 against the US dollar,'' he said.
Forsyth Barr broker Andrew Rooney said both UK and US stocks retreated on the poll result, which for the first time edged to 51% in favour of Scottish independence; 45% against.
''Stocks in energy producers fell as the price of oil dropped, leading to declines in the US and European markets,'' he said.
The British pound slid to a nine-month low point of $US1.6128 - before rebounding slightly to $US1.6143 - and dropped to 80.16 pence against the euro, which was the lowest for three weeks.
Michael Hewson, chief analyst at CMC Markets UK, said, ''Financial markets got a wake-up call this morning to the potential fall-out from a `yes' vote at the Scottish independence referendum in 10 days' time.
''The pound has slid sharply on the currency markets while the FTSE 100 has also come under pressure as companies with a significant Scottish presence have seen their share prices slide.''
Among the biggest decliners were Royal Bank of Scotland, which ended down 1.30% to 342.5 pence. US stocks finished mostly lower following disappointing economic data from China and Japan and the possibility of the Scotland split.
At the close on Monday, the Dow Jones Industrial Average stood at 17,111.42, down 25.94 points or 0.15%, while the broad-based S&P 500 fell 6.17, or 0.31% to 2001.54, while the tech-rich Nasdaq Composite Index rose 9.39, or 0.20%, to 4592.29.
''US equities are taking a breather following a five-week rally,'' Wells Fargo Advisers said in a note.
One of Scotland's leaders advocating independence said Scotland would share the pound with Britain, but the United Kingdom's Government ruled that out, leading to uncertainty about valuations, debt and the sharing of North Sea oil revenues.
- Additional reporting: AAP/Reuters
