By Lawrence DelevingneBOSTON, MA.(Reuters) – U.S. know-how giants are more and more dominating the stock market within the midst of the coronavirus pandemic, whilst they draw accusations of unfair enterprise practices, and a few buyers concern the pump is primed for a tech-fueled sell-off.The mixed value of the S&P 500’s 5 largest firms – Apple Inc <AAPL.O>, Amazon.com Inc <AMZN.O>, Microsoft Corp <MSFT.O>, Fb Inc <FB.O> and Google mother or father Alphabet Inc <GOOGL.O> – now stands at greater than $7 trillion, accounting for nearly 25% of the index’s market capitalization. That compares with lower than 20% pre-pandemic.The quintet’s burgeoning share costs replicate a transition to an more and more technology-driven economic system that has been accelerated by the coronavirus outbreak, as doorways fill with Amazon packages, homebound households stream motion pictures and pals commiserate on Fb.But the businesses are drawing opposition. U.S. lawmakers are accusing them of stifling competitors, a cost additionally leveled in current days in opposition to Apple by Epic Video games, creator of the favored recreation Fortnite.Some buyers fear the businesses powering this 12 months’s fairness rally may turn into the market’s Achilles’ heel if a authorized assault, a shift to undervalued names or a transfer increased in bond yields dries up urge for food for know-how stocks.”Folks see these firms as winners and buyers are prepared to pay any price to personal them,” mentioned Michael O’Rourke, chief market strategist at JonesTrading. “That is all the time a threat.”LEGAL THREATOne potential risk comes from an array of investigations and authorized actions.The most recent got here Monday, when a federal decide briefly blocked Apple from chopping off all of the developer accounts of Epic Video games, pending a full listening to on the problem. It was a partial win for Epic, which had referred to as Apple’s guidelines an anticompetitive abuse of energy.The standoff facilities on Apple’s App Retailer, which varieties the centerpiece of a $46.three billion-per-year companies enterprise that has helped buoy the corporate’s share price.The choice “is only a first battle of many on the horizon,” mentioned Dan Ives, an analyst at Wedbush Securities. “From a valuation perspective, there’s clearly an overhang round antitrust.”Wedbush nonetheless raised its goal price for Apple on Wednesday to $700 a share in a “bull case” situation, citing a “as soon as in a decade” alternative to make the most of as many as 950 million potential iPhone upgrades worldwide.Apple shares on Thursday closed at $500.04.Nonetheless, this week’s Apple court docket choice may be a style of issues to come back for know-how giants, whose affect has been one of many few points able to galvanizing bipartisan curiosity amongst lawmakers.Alphabet, Fb, Amazon and Apple face a collection of federal authorities probes into allegations that they unfairly defend their market share, with litigation in opposition to Alphabet potential later this 12 months.”These few behemoths dominate their business and might set the principles of the worldwide economic system,” mentioned U.S. Senator Richard Blumenthal, a Democrat who has been outspoken about antitrust points. “This sort of concentrated energy is all the time harmful.”The opposition is a fear for buyers hoping the businesses will proceed delivering strong progress that justifies their valuations.Amazon mentioned it operates in a “fiercely aggressive” market, citing U.S. Census Bureau knowledge that solely about 10% of U.S. retail gross sales happen on-line.Apple declined remark. The corporate beforehand mentioned it competes vigorously in opposition to Samsung Electronics Co Ltd <005930.KS> and different Android system makers within the sensible telephone markets. Alphabet declined remark. It beforehand mentioned it competes with Amazon, Microsoft, Comcast Corp <CMCSA.O>, AT&T Inc <T.N> and lots of others.Fb and Microsoft had no rapid remark.INVESTMENT DILEMMAFor some buyers, the businesses embody a dilemma that has dogged them at numerous instances over the past decade. Many have discovered that chopping publicity to tech-related shares has restricted portfolio efficiency over the long run.The Huge 5 have seen their shares leap 22% or extra to document highs this 12 months, with Amazon hovering 86%. By comparability, the median stock efficiency throughout the S&P 500 year-to-date is a 4% drop.Story continuesThe firms’ “elevated market share … gives probably large alternatives supporting progress prospects over a few years,” mentioned David Polak, fairness funding director at $1.7 trillion Capital Group, which owns shares of massive know-how firms.Nonetheless, some fear {that a} unhealthy patch within the firms’ extensively owned shares may set off violent swings in broader markets.Goldman Sachs analysts mentioned in a current report that the S&P 500 “has by no means been extra depending on the continued power of its largest constituents.”One other threat is a broad-based financial rebound boosting earnings of firms which have underperformed throughout the pandemic, probably making their shares extra aggressive with tech stocks, mentioned Edwin Jager, head of elementary equities at hedge fund agency DE Shaw & Co, which oversees greater than $50 billion. As well as, a sustained rise in bond yields may make progress stocks much less enticing, Jager mentioned. Longer-term Treasury yields hit multi-month highs on Thursday after the Federal Reserve introduced a shift in financial technique.A change of sentiment towards huge tech may take a relatively heavier toll on the shares of much less worthwhile know-how firms which have rallied alongside the market’s giants.Traders justify these stocks on the premise that “this time it is completely different,” mentioned Ed Cole, managing director of equities at $27 billion Man GLG. “It hardly ever ever is.”(Reporting by Lawrence Delevingne; Extra reporting by April Joyner, Stephen Nellis, Diane Bartz and Noel Randewich; Writing by Ira Iosebashvili; Enhancing by Megan Davies, Steve Orlofsky and Leslie Adler)