Shares of Credit Suisse surged on Thursday, rebounding from a fresh all-time low after the beleaguered lender announced that it would tap central bank support to shore up its finances.

Switzerland's second-largest bank said it would borrow up to 50 billion Swiss francs ($53.68 billion) from the Swiss National Bank, providing a moment of relief for investors after the Zurich-headquartered firm led Europe's banking sector on a wild ride lower during the previous session.

The Swiss-listed stock price was trading around 24% higher at 11 a.m. London time (7 a.m. ET) — a massive swing from Wednesday's more than 30% tumble after its biggest backer said it wouldn't provide further assistance due to regulatory restrictions.

The abrupt loss of confidence in Credit Suisse, which came as fears about the health of the banking system spread from the U.S. to Europe, has prompted some to question the "true" worth of Credit Suisse's stock price.

"We have to step back and look of course at the viability of the business model [and] at the overall regulatory landscape," Beat Wittmann, chairman of Switzerland's Porta Advisors, told CNBC's "Squawk Box Europe" on Thursday.

"I think the leadership of the bank has to really use now this lifeline to review their plan because obviously, the capital markets have not bought the plan as we have seen by the performances of the equity price and the credit default swaps very recently."

Asked for his views on the sharp fall of Credit Suisse's share price — which fell below 2 Swiss francs for the first time on Wednesday — Wittmann said a "brutal" monetary tightening cycle led by major central banks in recent months meant companies vulnerable to shocks were now beginning to "really suffer."

"The weakest links are cracking and that's just happening, and that was entirely predictable — and this will not be the last one. Now it is really time for policymakers to restore confidence and liquidity in the system, be it in the U.S., be it in Switzerland, or be it somewhere else," Wittmann said.

Asked for his advice to investors amid the market turmoil, he said: "The upside momentum in inflation and interest rates is receding very clearly so I think there is a very healthy underpinning in capital markets."

"But I would very strongly recommend sticking to high-quality companies — that means strong management, strong balance sheets, strong value proposition. And now you can pick them up at more attractive valuations," Wittmann added.

Even before the shock collapse of two U.S. banks last week, Credit Suisse has been beset with problems in recent years, including money laundering charges and spying allegations.

The bank's disclosure earlier this week of "material weaknesses" in its reporting added to investor concerns.

Credit Suisse management said Wednesday, however, that its latest step to secure a sizable funding deal showed "decisive action" to strengthen the business. They thanked the Swiss National Bank and the Swiss Financial Market Supervisory Authority for their support.

Analysts welcomed the move and suggested fears of a fresh banking crisis may be overstated.

"A stronger liquidity position and a backstop provided by the Swiss National Bank with the support from Finma are positive," Anke Reingen, an analyst at RBC Capital Markets, said Thursday in a research note.

"Regaining trust is key for the CS shares. Measures taken should provide some comfort that a spillover to the sector could be contained, but the situation remains uncertain," she added.

Analysts at UBS, meanwhile, said market participants were "grappling with three interrelated but different issues: bank solvency, bank liquidity, and bank profitability."

"In short, we think bank solvency fears are overdone, and most banks retain strong liquidity positions," they added.

For Dan Scott, head of multi-asset management at Swiss asset manager Vontobel — who used to work at Credit Suisse — it's not all bad news.

"I would say that Credit Suisse specifically is still one of the world's largest asset managers, it has half a trillion in assets, and certainly this could be a great turnaround story if the execution story is good," he told CNBC's "Squawk Box Europe" on Thursday.

Asked by CNBC's Geoff Cutmore whether this would mean investors staying patient despite market turbulence and the scale of outflows from the bank, Scott replied, "Absolutely. But I think again that the stress that we're seeing at the moment really should have been predictable."

"When rates go up so fast, certain business models get challenged and I don't think it is a wealth management business model that gets challenged. I think much more and why we saw it at Silicon Valley Bank, is private markets are going to be challenged," Scott added.