Oil prices climbed on the back of the weak dollar Getty

The FTSE 100 fell almost 4% in the first week of February, with commodity companies among the most volatile. On Friday (5 February), the bluechip fell 0.86% meaning that, five weeks into 2016, the index has lost 6.3% since the start of the year.

BG Group was the latest in a series of oil and gas producers to be hit by the ongoing slump in crude prices, as it saw its annual profit plummet by almost 40%, while the profit for the fourth quarter declined by more than 20% on the back of lower revenues.

In the 12 months to the end of December 2015, the FTSE 100 group posted a 39% year-on-year decline in earnings before interest, taxes, depreciation and amortisation to $5.63bn (£3.87bn, €5.02bn), while earnings per share plummeted 58% to 49.7 cents, it reported on Friday.

Shell, which has agreed to buy BG, reported on Thursday (4 February) that full-year profit plummeted 8% to $3.8bn. The Dutch oil company saw earnings on a current cost of supplies (CCS) basis tumble to $1.8bn in the last months of 2015 compared to$4.2bn for the same quarter in 2014.

However, IBTimes investment expert Edmund Shing said that now might be the perfect time to buy Shell shares, listing the company's size, prospective BG takeover and the cheap shares as reasons to invest. Oil prices also soared at the end of the week, as the US Dollar lost in value against other currencies.

Mining company Anglo American bounced back up on Thursday and Friday, after plummeting to new lows earlier in the week. The troubled company, which is suffering from the low commodity prices, announced a major restructuring that includes some 85,000 job cuts on 8 December. The "radical" changes set out by the company will result in almost two thirds (63%) of its workforce cut, from 135,000 to 50,000.

FTSE 100 risers*

Anglo American +9.73%
Antofagasta +4.11%
Standard Chartered +3.49%
Burberry +2.87%
Tesco +2.74%

FTSE 100 fallers

Berkeley -4.9%
Inmarsat -4.31%
Persimmon -3.38%
Sky -3.38%
Royal Mail -3.27%

FTSE 250 risers

Countrywide +7.08%
Evraz +6.02%
Entertainment One +5.81%
Ocado +5.71%
Vedanta Resources +5.67%

FTSE 250 fallers

Marshalls -7.72%
Domino's Pizza -6.31%
St Modwen Properties -5.27%
Thomas Cook -5.10%
Rightmove -4.25%

*Based on data provided by Hargreaves & Lansdown and the London Stock Exchange at close on 5 February (5.02pm)