Morning Business Memo…

The biggest story on global financial markets today is the collapse of gold and silver prices. Gold is down more than $90 an ounce since Friday - a fall of about 7 percent. The price drop comes on top of last week's 4.7 percent tumble. Silver prices tumbled 8 percent, or $24 an ounce. Copper is also falling. The reasons for the plunge are linked to the recent rise in the stock market, the slow, steady improvement of the US economy and the recent strength of the dollar. Crude oil futures have tumbled on global markets, down to less than $89 for West Texas crude, the lowest price since December, 2012. For years gold bugs have predicted economic apocalypse with hyper-inflation and a collapse of stock prices. That simply hasn't happened, and many investors have given up on gold, shifting funds out of precious metals. Last week Goldman Sachs issued a report, predicting gold prices would tumble. More volatility is expected in the days to come.

READ MORE: Gold has biggest two-day fall in 30 years.

Dish Network is offering to buy Sprint Nextel in a cash and stock deal worth more than $25 billion or $7 a share. The offer is in competition with a complicated bid for Sprint by the Japanese-owned telecommunications and Internet firm Softbank. Sprint's stock jumped 13 percent in pre-market trading. Sprint shares closed at $6.22 on Friday. Dish argues that the deal represents a premium to Softbank's proposal to buy 70 percent of Sprint for $20.1 billion. Softbank is seeking approval from U.S. authorities for its purchase that would be Japan's biggest foreign acquisition ever.

Medical tests are a growing business. Thermo Fisher Scientific is said to be close to a deal to buy genetic testing company Life Technologies. The bid is reported to be worth around $12 billion. Both sides held more talks yesterday.

A snapshot on housing. Today The National Association of Homebuilders releases its housing market index for April. It may show more improvement. This will be a busy week for first-quarter corporate profits. More than 70 big companies to report between now and Friday.

Richard Davies Business Correspondent ABC News Radio abcnews.com Twitter: daviesabc