去繁就简，ROIC可以分成三大部分：ROIC=NOPLAT/IC=（1-T）×EBIT/R×R/IC。 其中，（1-T）为刚性的，EBIT/R及R/IC两部分可以粗略勾画出某一公司的经营轮廓。

在巴菲特的笔下：

珠宝公司的周转率很慢，存货周转天数大约一年一次，以此推断IC的周转天数会更长。导致这个现象的原因是购买频率低、个人行为、货比三家，所以珠宝公司需要的IC比较大。

在资本逐利的本之下，为取得所有行业一般的ROIC，珠宝行当的EBIT/R自然比较高，一般珠宝商的定价（100%）原则是成本（50%）+营业费用（40%+）+期望利润空间（10%-），由于高昂的营业费用率（40%+），珠宝行当的税前利润率不到10%，ROIC更少的可怜,所以整个珠宝行业维持生计没有问题，但是绝不是一个吸引眼球的行业。

巴菲特旗下珠宝行的护城河在哪里呢？保证质量前提下的成本优势。Borsheim's的营业费用率仅为20%，所以Borsheim's可以采取低价策略（别人卖1350元的珠宝，巴菲特可以卖1000元），低价促进销售，营业费用进一步降低，所以Borsheim's的EBIT/R、R/IC高于行业水平。

当然，成本优势的战略有了，战术的实施同样需要优秀的管理团队。Ike 的经营让巴菲特百分之百的放心：网购的经营战术大获成功。

 所以：只有

1、了解投资的行业；

2、找到切入点（战略）；

3、 找到合适的人来实施（战术）；

才能，取得你期望的ROIC。

当然，巴菲特旗下的珠宝行护城河可以持续多久 （同行、潜在竞争者的模仿）也是值得留意的一点。

ps 巴菲特好像放弃ROE的分析框架了，呵呵。

You don't need to understand the economics of a generating plant in order to intelligently buy electricity. If your neighbor is an expert on that subject and you are a neophyte, your electric rates will be identical.

But jewelry purchases are different. What you pay for an item vs. what your neighbor pays for a comparable item can be, and often is, widely different. Understanding the economics of the business will tell you why.

To begin with, all jewelers turn their inventory very slowly, and that ties up a lot of capital. A once-a-year turn is par for the course. The reason is simple: People buy jewelry infrequently, and when they do, they are making both a major and very individual purchase. Therefore, they want to view a wide selection of pieces before zeroing in on a single item.

Given that their turnover is low, a jeweler must obtain a relatively wide profit margin on sales in order to achieve even a mediocre return on their investment. In this respect, the jewelry business is just the opposite of the grocery business, in which rapid turnover of inventory allows good returns on investment though profit margins are low.

In order to establish a selling price for their merchandise, a jeweler must add to the price they pay for that merchandise, both their operating costs and desired profit margin. Operating costs seldom run less than 40% of sales and often exceed that level. This fact requires most jewelers to price their merchandise at double its cost to them or even more. The math is simple: Jewelers charge $1 for merchandise that has cost them 50 cents. Then, from their gross profit of 50 cents they typically pay 40 cents for operating costs, which leaves 10 cents of pre-tax earnings for every $1 of sales. Taking into account the massive investment in inventory, the 10-cent profit is adequate but far from exciting.

At Borsheim's the equation is far different from what I have just described. Because of our single location and the huge volume we generate, our operating expense ratio is usually around 20% of sales. As a percentage of sales, our rent costs alone are fully five points below those of our typical competitor. Therefore, we can, and do, price our goods far below the prices charged by other jewelers. In fact, if they priced to match us, they would operate at very substantial losses. Moreover, in a virtuous circle, our low prices generate ever increasing sales, further driving down our expense ratio, which allows us to reduce prices still more.

How much difference does our cost advantage make? It varies by competitor but, by my calculation, what costs you $1,000 at Borsheim's will, on average, cost you about $1,350 elsewhere. This is called the “Borsheim’s Price”. There are very few instances where we are unable to offer you those great savings due to restrictions, but you will always know upfront if an item is non-discountable.

Of course, price means nothing unless you are sure of the quality of what you are getting. When products are branded, such as watches and chinaware are, comparisons are simple. But jewelry is usually a "blind" item - and that puts virtually all purchasers at the mercy of the seller.

I can remember well how helpless I used to feel in a Fifth Avenue or Rodeo Drive jewelry store, where the only thing I knew for sure was that the operator had extraordinarily high overhead - and that they had to cover it in their sales price. I was also wary of the "upstairs" solo operator who operated on consignment merchandise, since that would have cost them more than merchandise bought outright, and would necessarily have inflated their retail price. And, finally, I always worried about the quality of what I was getting I couldn't tell the difference between an emerald or a diamond worth $10,000 and one whose value was $100,000. (I still can't.)

My sense of helplessness led me to an obvious conclusion: "If you don't know jewelry, know your jeweler." For that reason, I made all of my jewelry purchases at Borsheim's for many years before Berkshire Hathaway bought the company. I didn't know stones, but I did know Ike Friedman, the retailing genius who had built the business from nothing into one of the nation’s largest independent jewelry stores. When I purchased Ike's business, I did it without an audit but with full confidence that I was getting value received. And that's just what I got - precisely as I had when I purchased a single piece of jewelry from him.

The main point of this letter is to tell you that you don't have to live near Omaha to benefit from Borsheim's. Our “shop-at-home” program brings Borsheim’s to our qualified customers. Simply contact Borsheim’s to describe what you’re looking for – to any degree of detail. We will assemble selections that best reflect your wishes and send them to you. Then, in the comfort of your own home or office, you can conveniently and leisurely select the item(s) you most prefer, or return the entire selection.

Our results from this "shop-at-home" program have been amazing. Customers have loved it and keep coming back for more. Each year, we send out several thousand packages, ranging in value from $100 to $500,000. Call us at