以前见过paid-in capital，也见过paid-up capital。没细研究，觉得差不多。
今天才知道，我错了。
首先是看到《韦氏法律词典》讲paid-up：
paid-up adj: requiring no further payment <a paid-up insurance policy>.
从释义来看，paid-up是“全额缴纳，无需补缴”的意思。
paid-in则在paid-in capital这个词条中，解释如下：
paid-in capital: equity capital that is received in exchange for an interest (as shares of stock) in the ownership of a business.
可见，paid-in capital才是“实缴资本”。
来看《元照英美法词典》的两个释义：
paid-up policy：缴清保单。人寿保险中，指保险费已全部支付的保险单。
paid-up stock = full(y)-paid stock
