(Bloomberg) -- It’s in the air again, on Reddit, in Congress, in the C-suite: Hedge funds that get rich off short-selling are the enemy. The odd thing is, the biggest players in the game are getting a pass.Those would be the asset managers, pension plans and sovereign wealth funds that provide the vast majority of securities used to take bearish positions. Without the likes of BlackRock Inc. and State Street Corp., the California Public Employees’ Retirement System and the Kuwait Investment Authority filling such an elemental role, investors such as Gabe Plotkin, whose Melvin Capital Management became a piñata for day traders in the GameStop Corp. saga, wouldn’t have shares to sell short.“Anytime we short a stock, we locate a borrow,” Plotkin said Feb. 18 at the House Financial Services Committee hearing on the GameStop short squeeze.There’s plenty to choose from. As of mid-2020, some $24 trillion of stocks and bonds were available for such borrowing, with $1.2 trillion in shares -- equal to a third of all hedge-fund assets -- actually out on loan, according to the International Securities Lending Association.It’s a situation that on the surface defies logic. Given the popular belief that short sellers create unjustified losses in some stocks, why would shareholders want to supply the ammunition for attacks against their investments? The explanation is fairly straight forward: By loaning out securities for a small fee plus interest, they can generate extra income that boosts returns. That’s key in an industry where fund managers are paid to beat benchmarks and especially valuable in a world of low yields.The trade-off is simple: For investors with large, diversified portfolios, a single stock plummeting under the weight of a short-selling campaign has little impact over the long run. And in the nearer term, the greater the number of aggregate bets against a stock -- the so-called short interest -- the higher the fee a lender can charge.In the case of GameStop, short interest was unusually high and shares on loan were generating an annualized return of 25% to 30%, Ken Griffin testified at the Feb. 18 hearing. Griffin operates a market maker, Citadel Securities, as well as Citadel, one of the world’s largest hedge funds.“Securities lending is a way for long holders to generate additional alpha,” said Nancy Allen of DataLend, which compiles data on securities financing. “Originally, it was a way to cover costs, but over the last 10 to 15 years it’s become an investment function.”Not everyone is comfortable with the inherent conflict. In December 2019, Japan’s $1.6 trillion Government Pension Investment Fund stopped lending its international stock holdings to short sellers, calling the practice inconsistent with its responsibilities as a fiduciary. At the time, the decision cost GPIF about $100 million a year in lost revenue.The U.S. Securities and Exchange Commission has regulated short-selling since the 1930s and polices the market for abuses such as naked shorting, which involves taking a short position without borrowing shares. Proponents of legal shorting argue that its use enhances liquidity, improves pricing and serves a critical role as a bulwark against fraud and hype.Chief executives, whose pay packages often depend on share performance, routinely decry short sellers as vultures. More recently, shorting has come under fire in the emotionally charged banter on Reddit’s WallStreetBets forum. Some speculators ran up the prices of GameStop, AMC Entertainment Holdings Inc. and other meme stocks in January to punish the hedge funds that bet against them, and they delighted when the rampant buying led to bruising losses at Melvin, Maplelane Capital and Citron Research.Many of the key actors in the GameStop frenzy testified at the Feb. 18 hearing. Plotkin was grilled by committee members over Melvin’s short position. Citadel’s Griffin and others faced broader questions about short-selling. Yet no one asked about the supply of borrowed shares and there were no witnesses called from the securities-lending industry.There’s a symbiotic relationship between hedge funds and the prime-brokerage units of Wall Street firms, much of it built on securities lending. Prime brokers act as intermediaries, sourcing stocks and bonds for borrowers who want to short them and facilitate the trades. According to DataLend, securities lending generated $2.9 billion of broker-to-broker revenue in 2020, almost the same as in 2019.Demand for short positions was already expected to drop as stock prices surged to all-time highs. Now, with the threat of retribution from the Reddit crowd, it may weaken even further. Griffin said he has “no doubt” there’ll be less short-selling as a consequence of the GameStop squeeze.“I think the whole industry will have to adapt,” Plotkin said at the hearing. “I don’t think investors like myself want to be susceptible to these types of dynamics.”This could not only threaten the dealers who broker stock lending but also the holders who supply the securities and share in the revenue. They reaped $7.7 billion globally in 2020, down from a record of almost $10 billion in 2018, according to DataLend. Lending fees increased by 4.2% on a year-over-year basis in February after the GameStop onslaught, DataLend says.While securities lending accounted for $652 million, or just 4%, of BlackRock’s revenue in the fourth quarter of 2020, there’s little cost involved and the risks are low because borrowers have to put up collateral that equals or exceeds the value of the loan. At both BlackRock and State Street Corp., the second-largest custody bank, the value of securities on loan as of Dec. 31 jumped at least 20% from a year earlier, to $352 billion and $441 billion, respectively.“Every little bit counts with indexes,” said John Rekenthaler, vice president of research at Morningstar. “You’re scraping nickels off the street, but there’s a whole lot of nickels.”Others could take a hit, too. Just as Robinhood Markets is able to offer zero-commission trades by selling its order flow to Citadel and other market makers, asset managers typically pass on some of their securities-lending revenue as a type of client rebate.“It’s very important to remember that institutional investors earn substantial returns from participating in the securities-lending market,” Citadel’s Griffin said at the GameStop hearing. “That accrues to the benefit of pension plans, of ETFs, of other pools of institutional lending that participate in the securities lending market.”(Adds data on lending fees after the short-interest chart.)For more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.©2021 Bloomberg L.P.