Credit Spread......limited loss. Sell naked Call........unlimited loss.....or be short the underlying if option exercised. Sell naked Put.....potential for large loss......or be long the underlying if option exercised. Credit spreads are much less risky & have lower margin requirements.
Define what you mean by "risky." Are you thinking of a dollar amount? One is limited, one is (theoretically) unlimited. Are you thinking of probability-of-occurrence? The probabilities are the same.
Credit Default Swaps are as risky as naked OTM put options....in many ways mirror images of each other. They are often spread against each other OTC. http://www.fmaconferences.org/HongKong/Papers/DOOM_CDS_Trading_v1.2.pdf
If you bought a 10 yr junk bond and sold a 10 yr US Treasury Note against it to lock in the credit spread, you have just as much risk or maybe more as selling a naked put on the company, if the company (the junk bond issuer) goes out of business. Depends how far OTM the puts are. So yes. Buying high yield credit spreads can be just as risky as selling naked OTM puts.
Think about ROI, though. If the market moves to the long leg of my credit spread then I have the opportunity to lose 100% on my investment even though the margin requirement may be a fraction of the corresponding naked. In case of the latter, a move to that long strike would result in a finite percentage loss of the Reg T margin requirement. I think this can also confuse the notion of leverage. I may be able to sell five spreads and carry a lower notional risk than the naked equivalent but still be a higher risk because a move to that long strike would wipe out 100% of the spread capital at risk vs. a smaller percentage of the Reg T naked margin requirement.
Looking @ options trading from a % rather than $$ is a mistake IMO. Options trading will usually have greater % returns/losses but the focus should be on the $$$. Calculate trade size based upon $$$ at risk and look @ that amount in relation to your entire account rather than 1 individual trade. If you can afford to lose the $$ amount then don't worry about losing 100% of a trade. Here's an example: XYZ trading @100 Sell 110/120 call spread for 5. XYZ goes to 150. Trade result: I lose 5 which is 100% of margin required. Same stock example except I sell 110 naked put for 10. Trade result: I lose 30 which is smaller % of margin required. Compare: Call spread lost 5 but 100% of margin. Naked call lost 30 but smaller % of margin. So would you rather lose $5 (100% of trade margin) or $30 (smaller % of margin)??? I prefer the $5 loss regardless of the 100% margin loss.