为什么不涉及基差风险basis risk ？

NO.PZ201601050100000403 问题如下 3. Given the recent movement in the forwarpremium for the SEK/EUR rate, Björk cexpeththe hee will experienhigher: A.basis risk. B.roll yiel C.premia income. B is correct.To hee the EUR-nominateassets Björk will selling forwarcontracts on the SEK/EUR cross rate. A higher forwarpremium will result in higher roll return Björk is selling the EUR forwara higher all-in forwarrate, anclosing out the contraa lower rate (all else equal), given ththe forwarcurve is in contango.A is incorrebecause Björk is heing EUR-nominateassets with a EUR-nominateforwarcontract. While it is true ththe gbetween spot anforwarrates will higher the higher the interest rate fferentibetween countries, this g(basis) converges to zero nematurity te, when the forwarcontracts woulrolleC is incorrebecause forwarcontracts not generate premia income; writing options es.中文解析这道题目从roll yiel公式来判断。首先明确一下持有的是外币EUR的资产，因此是short forwaron SEK/EUR。此时roll yiel计算式子是F-S/S。而forwarpremium指的是F S，所以根据roll yiel公式可知，roll yiel正，即有更高的roll yiel。C指的是期权费，本题不涉及，A的基差风险本题也不涉及。

NO.PZ201601050100000403 问题如下 3. Given the recent movement in the forwarpremium for the SEK/EUR rate, Björk cexpeththe hee will experienhigher: A.basis risk. B.roll yiel C.premia income. B is correct.To hee the EUR-nominateassets Björk will selling forwarcontracts on the SEK/EUR cross rate. A higher forwarpremium will result in higher roll return Björk is selling the EUR forwara higher all-in forwarrate, anclosing out the contraa lower rate (all else equal), given ththe forwarcurve is in contango.A is incorrebecause Björk is heing EUR-nominateassets with a EUR-nominateforwarcontract. While it is true ththe gbetween spot anforwarrates will higher the higher the interest rate fferentibetween countries, this g(basis) converges to zero nematurity te, when the forwarcontracts woulrolleC is incorrebecause forwarcontracts not generate premia income; writing options es.中文解析这道题目从roll yiel公式来判断。首先明确一下持有的是外币EUR的资产，因此是short forwaron SEK/EUR。此时roll yiel计算式子是F-S/S。而forwarpremium指的是F S，所以根据roll yiel公式可知，roll yiel正，即有更高的roll yiel。C指的是期权费，本题不涉及，A的基差风险本题也不涉及。 backwartion情况下roll yiel= (SP0 - FP0) / SP0 ；contango情况下roll yiel= (FP0 - SP0) / SP0；Q1公式是对的嘛？有点记不清了；Q2roll yiel样计算是不是永远是正数呢？

NO.PZ201601050100000403问题如下3. Given the recent movement in the forwarpremium for the SEK/EUR rate, Björk cexpeththe hee will experienhigher:A.basis risk.B.roll yielC.premia income. B is correct.To hee the EUR-nominateassets Björk will selling forwarcontracts on the SEK/EUR cross rate. A higher forwarpremium will result in higher roll return Björk is selling the EUR forwara higher all-in forwarrate, anclosing out the contraa lower rate (all else equal), given ththe forwarcurve is in contango.A is incorrebecause Björk is heing EUR-nominateassets with a EUR-nominateforwarcontract. While it is true ththe gbetween spot anforwarrates will higher the higher the interest rate fferentibetween countries, this g(basis) converges to zero nematurity te, when the forwarcontracts woulrolleC is incorrebecause forwarcontracts not generate premia income; writing options es.中文解析这道题目从roll yiel公式来判断。首先明确一下持有的是外币EUR的资产，因此是short forwaron SEK/EUR。此时roll yiel计算式子是F-S/S。而forwarpremium指的是F S，所以根据roll yiel公式可知，roll yiel正，即有更高的roll yiel。C指的是期权费，本题不涉及，A的基差风险本题也不涉及。 是英文阅读理解问题么？如果理解为将hee euro资产，现在short forwar以理解为有roll yiel如果理解为已经heeeuro资产，已经持有short头寸（即已经卖空forwar约），如何理解有roll yiel

NO.PZ201601050100000403问题如下3. Given the recent movement in the forwarpremium for the SEK/EUR rate, Björk cexpeththe hee will experienhigher:A.basis risk.B.roll yielC.premia income. B is correct.To hee the EUR-nominateassets Björk will selling forwarcontracts on the SEK/EUR cross rate. A higher forwarpremium will result in higher roll return Björk is selling the EUR forwara higher all-in forwarrate, anclosing out the contraa lower rate (all else equal), given ththe forwarcurve is in contango.A is incorrebecause Björk is heing EUR-nominateassets with a EUR-nominateforwarcontract. While it is true ththe gbetween spot anforwarrates will higher the higher the interest rate fferentibetween countries, this g(basis) converges to zero nematurity te, when the forwarcontracts woulrolleC is incorrebecause forwarcontracts not generate premia income; writing options es.中文解析这道题目从roll yiel公式来判断。首先明确一下持有的是外币EUR的资产，因此是short forwaron SEK/EUR。此时roll yiel计算式子是F-S/S。而forwarpremium指的是F S，所以根据roll yiel公式可知，roll yiel正，即有更高的roll yiel。C指的是期权费，本题不涉及，A的基差风险本题也不涉及。 外币价格资产上涨short方不是赔钱了吗？为什有roll yiel这个公式看不懂