Most income-generating stocks pay out dividends on a quarterly basis. That schedule might be fine for many investors, but retirees living off dividend income might prefer monthly payments instead.

Let's check out three high-yielding investments that fit that bill -- BlackRock Enhanced Capital and Income (NYSE:CII), Eaton Vance Tax-Managed Buy-Write Income (NYSE:ETB), and Shaw Communications (NYSE:SJR).

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BlackRock Enhanced Capital and Income

BlackRock Enhanced Capital and Income is an indexed ETF (exchange traded fund) that contains a diversified basket of nearly 80 well-known stocks like AppleAlphabet, JPMorgan Chase, Comcast, and Microsoft. The ETF currently pays a monthly dividend of $0.10 per share, which translates to an annual yield of 8.6%.

The fund can afford to pay that high yield because it constantly sells covered call options to boost its cash flow. With this strategy, the fund writes call options on its own stocks, which grant buyers the right to purchase the stock at the current price if it rises to a predefined "strike" price. Whether or not the option is exercised or expires, the fund retains the premium paid by the buyer. The price of option premiums generally rise in more volatile markets, meaning that the fund's cash flows from covered calls can offset the volatility of its underlying holdings in choppier markets.

The downside of this strategy is that the fund's gains from its own holdings are limited as the call buyers exercise their options to sell the rising stocks. This means that while the fund is unlikely to ever outperform the market, it's a solid income-generating hedge against volatility. Moreover, the ETF currently trades at a 5% discount to its NAV (net asset value), indicating that its downside potential is fairly limited.

Eaton Vance Tax-Managed Buy-Write Income

Eaton Vance Tax-Managed Buy-Write Income is another high-yielding ETF very similar to BlackRock Enhanced Capital and Income. The fund also owns a basket of blue-chips like Apple, Microsoft, Wells Fargo, Chevron, and Johnson & Johnson, and pays a monthly dividend of $0.11 per share -- which translates to a yield of 8%.

The fund uses a similar covered call strategy as BlackRock to boost its cash flow and fund dividends, so it has the same strengths and weaknesses. However, the Eaton Vance fund is a slightly less attractive ETF for two reasons -- it trades at a 4% premium to its NAV, and has a slightly lower dividend yield.

Shaw Communications

If the world of ETFs and covered call options seems too complicated, Canadian telco Shaw Communications might be a better income play. The company pays a monthly dividend of about $0.10 CAD per share ($0.08 USD), which equals a 4.5% yield. Shaw hasn't hiked its payout every year, but it's paid uninterrupted dividends for almost two decades.

Like many major telcos, Shaw is losing landline customers to wireless services and cable subscribers to cord cutting. However, the company recently diversified into wireless services with its acquisition of Wind Mobile, sold its media business, and is raising prices on existing customers to offset its loss of core customers. As a result, Shaw's revenue rose 13% annually last quarter, and its GAAP profits more than tripled. But after excluding discontinued operations, its earnings per share actually fell from $0.28 a year ago to just $0.11.

Shaw paid out about 97% of its free cash flow as dividends over the past 12 months. That ratio looks uncomfortably high, but it should decline if Shaw's big strategic shift pays off. While the company might suspend dividend hikes, it's unlikely to reduce the dividend unless its strategy completely falls apart.

Should you buy these monthly income generators?

I personally own shares of BlackRock Enhanced Capital Income, and I believe that it's the best pick on this list because it has a great yield and trades at a discount to its NAV. The Eaton Vance fund might look more attractive at lower prices in the future.

As for Shaw, I think it's a stable telco for monthly dividends, but investors who don't need monthly payments should just buy AT&T or Verizon instead -- which both offer comparable yields with much lower payout ratios.