Right now, the fabled 145-year old investment bank is leading the news on Wall Street. For good or ill, Goldman (GS) remains an object of intense fascination. It’s getting pounded in the press over a whistleblower’s charges that it received special treatment from regulators at the New York Fed. According to a story on the public interest website ProPublica, Fed officials were so intimidated by the Goldman brass that they failed to block transactions that were as suspicious as they were lucrative—allegations Goldman vehemently denies. At the same time, Goldman recently confirmed its stature by overseeing early trading for Alibaba’s (BABA) historic IPO.

But how good, really, is Goldman Sachs? An analysis of its recent performance reveals that, for the present at least, Goldman is nowhere near the champion of old. Its record ranks somewhere between pretty good and mediocre. Its businesses, and the environment in which it operates, have shifted dramatically, and not in Goldman’s favor. The kind of adventurous investments that once swelled its earnings are now off-limits.

“In contrast to the past, they’re being extremely conservative in the way they’re managing, and it will take a couple of years to see how they adapt to the new environment,” says Keith Davis, a portfolio manager with Farr, Miller & Washington, which holds $20 million in Goldman shares.

The fear is that Goldman has run out of moves.

Goldman’s path forward is restricted by two barriers. First, its main franchise is now trading, a business that, for the time being, isn’t terribly profitable. The dominance of trading—making markets in stocks, bonds, commodities and currencies—represents a sharp break with the past. In 2000, 60% of its sales came from advising on mergers and acquisitions, raising money for corporations, and asset management. In 2013, those high-margin businesses accounted for just 37% of Goldman’s $34 billion in revenues. So the mix is now tilted toward a field that’s depressed, where a long-awaited rebound just isn’t happening.

Second, Goldman has traditionally generated big profits from “principal investments,” using its own capital to trade in and out of stocks, take ownership positions in companies, and invest in private equity and hedge funds. The Volcker Rule, a pillar of the Dodd-Frank banking reform legislation, bans proprietary trading and severely restricts the investments banks can make. This formerly lucrative channel is now mostly closed to Goldman.

As a result, Goldman’s profitability has suffered. From 2005 to 2007, Goldman delivered a spectacular return on equity of, on average, 28.4%. Since then, the bank has enjoyed just one excellent year. That was 2009, when markets began to thaw after the financial crisis and investors dumped bonds en masse, handing Goldman both huge volumes of trades and fantastic margins, or “spreads,” on those trades. Since 2012, its ROE has dropped to an average of 10.5% to 11%.

Still, that’s not bad. A major reason for the decline: new regulations have forced all banks to lower their leverage. Goldman used to support $20 in assets with every dollar of equity; today, a dollar in net worth backs just $10.50 in assets. That’s a good thing, since it should smooth the big swings in returns caused by high levels of debt. An ROE in the 10% to 11% range also looks good in a period where investors pocket just 2.5% on 10-year Treasury bonds. And Goldman’s ROE compares favorably to its rivals. Though it trails Wells Fargo (13.6%) and US Bancorp (12%), it waxes JP Morgan (8.3%), Citigroup (6.7%), and Morgan Stanley (6.5%).

For Goldman, the challenge is that an 11% ROE may be acceptable for now, but it will be far from adequate once interest rates rise. With treasuries back at their historic norms of 4% or 5%, and highly rated corporate bonds offering a couple of points more, investors will want better things from the likes of Goldman. Its profits, dominated by trading, are still vulnerable to sharp declines. In 2011, for example, Goldman earned a puny ROE of 3.6%. By contrast, the big banks can practically guarantee large increases in profits and ROE as interest rates increase. When that happens, they’ll benefit handsomely from the rising spread between the low-cost deposits and the rates on their mortgages and corporate loans.

It would bolster confidence if Goldman’s numbers were headed in the right direction. They’re not. Goldman is having difficulty finding profitable places to reinvest its earnings. It has essentially admitted as much by re-purchasing $12.2 billion in its own shares since 2011. But it’s still investing much of its earnings in the businesses, and those fresh investments are garnering sub-par returns. Since 2005, its common equity base has increased from $23.5 billion to $74.4 billion, an increase of $51 billion. But over those eight years, it’s added just $3.25 billion in earnings. So the return on newly added equity is a mere 6.4%.

Nor is the recent story reassuring. In the 12 months from June 2013 to June 2014, Goldman added $1.6 billion in capital. Its 12-month trailing earnings during that period, however, declined from $8.4 billion to $7.6 billion. So its ROE, driven by higher capital and lower profits, actually dropped from 11.8% to just over 10.6%.

These sluggish returns have been weighed down by Goldman’s primary franchise, trading. Today, Goldman holds an inventory of around $350 billion in securities that it has purchased from clients, and seeks to resell, at the widest margins possible. From 2008 to 2010, Goldman earned an average of 3.8% on its trading book. But since 2011, the margin has dwindled to a slender 1.2% to 1.3%.

The problem is basic: That inventory isn’t “turning over” nearly as fast as it used to, because hedge funds, mutual funds, and other clients have slowed the pace of their trading. Nor are spreads nearly as rich as in the aftermath of the financial crisis.

To return to its glory days, Goldman will need to generate far higher returns on that trading book. That’s the ticket to driving returns on equity to heights that would prove alluring in the coming, rising-rate environment of tomorrow.

In its 2013 proxy statement, Goldman revealed that it has set a 12% ROE target for a full payout on its long-term compensation plan. That’s an increase from just 10%, a surprisingly modest goal for such a hard-charging management team. But to reach even 12%, Goldman still has a ways to go.

“The 12% target is still a low bar,” says Davis. “I’m thinking 14% to 16% is where they should be.” He believes Goldman will get there. “If they can’t get to a 15% ROE in a business, they’ll get out of it,” he says. “It will take them a couple of years to get through it. If anyone can figure it out, they can.”

Indeed, when interest rates rise, trading could explode as investors pile into bonds. That trend would produce what Goldman needs most: A jump in turnover and margins in its big securities portfolio. Goldman fans also argue that because of the new capital requirements, big banks have exited fixed income, currency, and commodities trading. Hence, Goldman could find itself in a more commanding position than at any time in its recent history.

That scenario is certainly possible. It’s also possible that bond trading, Goldman’s strength, could go the way of market making in equities. Once highly lucrative, stock trading has become a low-margin, commoditized field executed on electronic platforms. New banking regulations mandate that derivatives go electronic as well. If the opaque bond market becomes more, rather than less, competitive, Goldman will fail to restore its once-sovereign profitability. If fixed income booms again—and especially if Goldman emerges as the unchallenged king of bond trading—it will be on the road to a great restoration. Think of it as the Yankees capturing yet another World Series.