There is no special approach that they do. They're the same as us, they can do multisig, use hardware wallets or even paper wallets. Depending on how confident they are with how they store their Bitcoin holdings.

Those that are hired to maintain and keep these company wallets probably have signed their own contracts, the NDAs and they're paid very well to protect it. So someone doing a foul play with their wallets, it's close to impossible if they are keeping it with multisigs and a hardware wallet that's kept on a vault.

It is certainly their right to secrecy and probably they will only talk about numbers with percentages that are likely to be known to the public. What kind of business are you talking about and how does it relate to the substance of the discussion we are discussing? There are many who come to bitcoin and it is more than just small companies, large and institutions, maybe the greater adoption will have an impact on the steps of guarding their assets and that is why the substance of the discussion is more about the use of much more secure wallets that will be used.

Spending large amounts of money must definitely think about the level of security and that is in line with what we want to hear. If not there is probably no point for companies to buy wallets especially for storing their bitcoins and if we refer to some of the things that have been explained maybe there we will find the answer.

The best method depends on the company's bitcoin volume transaction frequency and security requirements. Generally large companies use a combination of multiple methods big companies use different techniques and technologies to store bitcoins. Considering the volatility of bitcoin and the risk of hacking these storage methods are tried to be very secure and reliable. They are hardware wallets these wallets are used to store the bitcoin private key offline as it is the most secure option from hackers. Cold storage is also an advanced version of bitcoin storage for large companies it has multiple levels of security features and is commonly used to store large amounts of bitcoin.