Following yesterday's thumping, investors were clearly hopeful that the broad-based S&P 500 would mount some form of comeback on Friday and gives optimists some hope. That hope, however, evaporated quickly.

The main culprit again was the heavy selling pressure in momentum stocks that had led this rally, especially in the biotechnology and technology sectors. Valuations have been rising precipitously in recent months and investors may finally be hitting the ceiling as to what type of forward multiple or optimism they're willing to accept.

Even positive economic data couldn't help stem the downward pressure.

The Thomson Reuters/University of Michigan preliminary index of consumer sentiment rose to 82.6 in April, its highest level since last July. Amazingly, this reading comes as the market has been vacillating as wildly as anything we've witnessed in almost a year. A higher sentiment reading would signify that consumers feel more confident about their short and longer-term economic outlooks which portends well for consumer spending.

In addition, the Producers Price Index rose a robust 0.5% in March on the heels of a 0.7% jump in final demand services. This was a nice reversal from the 0.1% decline in February, and it handily trounced Wall Street's expectation of a 0.1% increase. Even so, as Fool Justin Loiseau pointed out, underlying prices were mixed, with food prices up more than 1% and energy prices dipping by more than 1%.

By day's end the S&P 500 had digested this positive data and thrown it out the window in favor of biotech and tech fearmongering, pushing the index down 17.39 points (-0.95%) to close at 1,815.69. The index has now lost nearly 4% since April 2. Yet in spite of the tumble, three stocks roared to the upside.

Topping the charts today was precision measurement solutions and optical subsystems and components manufacturer Zygo (NASDAQ: ZIGO), which gained 32.4% after agreeing to be purchased by Ametek (NYSE:AME) for $19.25 per share in cash. The overall enterprise value, including warrants, values the company at $280 million. As per the norm, the deal is still contingent on shareholders' approval, though MAK Capital One, a financial advisory firm that is a large stakeholder in Zygo and is controlled by Zygo board Chairman Michael Kaufman, has agreed to vote in favor of the buyout. With Ametek's top-line growth expected to dip into the middle single digits in 2015, I can see where this move could easily add to its top and bottom-line figures. However, if I were a Zygo shareholder I might consider cashing in my chips now; with the stock closing 1% above the buyout offer price I don't see much likelihood of another buyer swooping in, or Ametek's offer being raised.

Source: Thompson Creek Metals.

Gold, copper, and molybdenum miner, and also my largest portfolio holding, Thompson Creek Metals (OTC:TCPTF) tacked on 9.2% less than two days after updating its operational progress at its newly opened Mt. Milligan mine. For the quarter, Thompson Creek noted total concentrate production of 28,200 dry metric tons which contained 14.2 million pounds of payable copper and 39,200 ounces of payable gold. Molybdenum production at its Thompson Creek mine came in ahead of expectations, while the Endako Mine disappointed again. Overall, the ramp up of Mt. Milligan since it hit the production stage has gone off without a hitch. I believe Thompson Creek could really surprise investors this year even if gold and copper prices vacillate around the flatline. I would urge metal-savvy investors to add this name to your watchlist.

Finally, Internet banking specialist Bofi Holding (NYSE:AX) advanced 8.1% after striking a deal to acquire H&R Block's (NYSE:HRB) banking assets. As a result of the deal, which Fool Jordan Wathen has done a fantastic job of laying out, Bofi should generate $26 million-$28 million in H&R Block program management fees beginning next year. As Jordan notes, although we don't have a disclosed price for this transaction as of yet, it allows Bofi to expand its presence into short-term personal loans, as well as expand its cross-selling capabilities with the addition of some 300,000 IRA customers. Bofi's growth rate already made the company attractive prior to this transaction, so you can only imagine what I think about the company now.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.