The increase in fulfillment centers can be viewed as an investment in future growth and perhaps margins assuming better efficiencies, but an increase in variable costs per revenue can signal permanently declining margins.

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Two days ago, Forbes first reported that Morgan Stanley had been served earlier with a subpoena by Massachusetts Secretary of the Commonwealth William Galvin seeking details of its variable annuity sales, including revenue-sharing arrangements, compensation, whether the products receive preferred sales treatment, commission schedules, prospectuses and documents for internal use only (see: " Morgan Stanley Subpoenaed Over Annuity Sales").

FORBES: Morgan, Merrill Face Lawsuits Over Annuities

Looking at the variation in the cheapest tickets offered across games shows that variable pricing is a more efficient method of revenue management and maximization.

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While revenue sharing costs and postage costs are variable, other costs have large fixed components.

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Variable annuities can be particularly profitable because of high upfront fees and ongoing revenue from the securities.

FORBES: Morgan Stanley Subpoenaed Over Annuity Sales

Last year, there was a significant increase in the ratio of variable staff costs to total staff costs, rising to 13.4 percent and as a proportion of revenue, rising to 7.8 percent, representing the highest ratios for the last 10 years.

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Dornan's class action alleges that at least since 1990 variable annuity underwriters and Morgan Stanley maintained "secret contingent fee sharing arrangements" in which a portion of commission revenue was paid to the brokerage as an incentive to sell the product.

FORBES: Morgan, Merrill Face Lawsuits Over Annuities